How infants perceive a simple causal event.

Four experiments examined 10-mo-old infants' causal event perception. Exp 1 replicated previous studies except that the specific objects used as agent and recipient varied from trial to trial. Under these conditions infants did not process the causality. Instead they keyed on specific temporal and spatial differences among the events. Exp 2 showed that infants notice a change in the particular agent performing either a causal or noncausal action. Exp 3 showed that infants do not notice a change in the type of action done to a particular recipient. Exp 4 demonstrated that infants do not pay attention to the object used as a recipient. As a whole, the results indicate that 10-mo-old infants perceive the causality of simple events by associating a specific agent with the causal action. These results provide more support for an information-processing view than for the view that infants have a causal module. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Continuous infusion of porcine factor VIII in the management of patients with factor VIII inhibitors

Increased detection thresholds for pure tones were observed in a large cohort of children exposed to lead environmentally while smaller studies in lead-exposed workers have reported conflicting results on assessments of auditory function. Pure tone detection thresholds were determined in a group of monkeys (Macaca fascicularis) dosed with 2 mg/kg/day of lead from birth through testing at 13 years of age. Blood lead concentrations were stable at about 30 micrograms/dl until monkeys were 10-11 years of age at which time they increased to between 50 and 70 micrograms/dl. Five age- and rearing-matched monkeys served as controls. Detection thresholds were determined at six frequencies between 0.125 and 31.5 kHz. Ear phones were fit over both ears, and thresholds were determined for each ear separately. The monkey signaled detection of the tone by breaking contact with a stainless steel bar. Three lead-exposed monkeys exhibited normal pure tone detection functions. Three monkeys had thresholds outside of the control range at some frequencies; there was a tendency for higher frequencies to be differentially more affected. These findings are consistent with reports of elevated pure tone thresholds in humans exposed to lead developmentally, although the effect is smaller than might have been predicted given the concurrent blood lead concentrations of these monkeys.     

A monitoring, feedback, and triggering system for reproducible breath-hold MR imaging

OBJECTIVE: To evaluate the diagnostic accuracy and clinical usefulness of high-resolution transvaginal duplex Doppler ultrasound in postpartum and post-abortion patients with excessive hemorrhage who are suspected of having residual trophoblast. METHODS: Forty-eight women with excessive hemorrhage referred for possible residual trophoblastic tissue were evaluated by transvaginal duplex Doppler ultrasonography. Based on two-dimensional imaging, the patients were divided prospectively into groups: women who had an empty uterus with a normal uterine cavity, those with a pure endometrial fluid collection and no echogenic foci, those who had a mixed endometrial fluid collection with foci of echogenicity, and those with intracavitary heterogeneous material with mixed echo patterns of fluid and solid components. In each group, Doppler studies were performed and the resistance index (RI) was calculated. The two-dimensional patterns and Doppler results were correlated with clinical and pathologic follow-up. RESULTS: Twenty-eight subjects had a normal uterine cavity and seven had a pure endometrial fluid collection; all were treated conservatively and none showed later clinical evidence of residual trophoblastic tissue. In 13 women, residual trophoblast was strongly suggested from the images of two-dimensional ultrasonography: Five showed an endometrial fluid collection with some echogenic foci, and eight exhibited intracavitary mixed echogenic material. All underwent curettage, and residual trophoblastic tissue was found in ten of the 13. The mean (+/- standard deviation) RI to flow in the myometrial arteries was 0.54 +/- 0.15 in women without residual trophoblast and 0.35 +/- 0.1 in those with residual trophoblastic tissue (P < .01). CONCLUSION: Our experience suggests that transvaginal duplex Doppler ultrasonography is an effective noninvasive method for evaluating patients with excessive postpartum and post-abortion hemorrhage who are suspected of having residual trophoblastic tissue. Its use enhances the positive preoperative diagnosis of residual trophoblastic tissue and may reduce unnecessary curettage procedures.     

The role of mineralocorticoid receptors in hypothalamic-pituitary-adrenal axis regulation in humans

In rodents, two types of glucocorticoid receptors, the mineralocorticoid (MR; type I) and the glucocorticoid (type II) receptors, have been demonstrated to play a role in hypothalamic-pituitary-adrenal (HPA) axis regulation. Because MR shows a very high affinity for cortisol, it has been suggested that MR plays an important role in restraint of CRH and ACTH secretion during the nadir of the circadian rhythm. Although a number of studies have established the importance of MR in rodents, the functional role of MR in humans has not been determined. These studies evaluated whether spironolactone, an MR antagonist, had a detectable effect on HPA axis regulation in humans, and whether the effect was greatest during the evening, when plasma cortisol concentrations are in the MR range. Compared to the placebo day, after a single dose of spironolactone at either 0800 or 1600 h, there is a significant increase in plasma cortisol, which is preceded by a rise in ACTH and beta-endorphin. A significant effect of spironolactone on cortisol secretion was demonstrated with no differences between the morning and evening. Because the effect of spironolactone on cortisol was short lived, a second experiment was conducted using two doses of spironolactone, again sampling in the morning and evening. After two doses of spironolactone, plasma cortisol levels showed a significant and sustained spironolactone-induced elevation for the entire sampling period. However, neither plasma beta-endorphin nor ACTH was increased compared to levels on the placebo day. These data suggest that MR appear to play a clear role in HPA axis regulation during the time of the circadian peak as well as the trough. Furthermore, MR blockade may affect the sensitivity of the adrenal to ACTH.     

Retroviral display of antibody fragments; interdomain spacing strongly influences vector infectivity

Five different single-chain antibody fragments (scFv) against human cell-surface antigens were displayed on murine ecotropic retroviral vectors by fusing them to the Moloney SU envelope glycoprotein. The spacing between the scFv and the SU glycoprotein was varied by fusing the scFv to residue +7 or to residue +1 of Moloney SU and by inserting linker sequences of different lengths between the domains. All of the chimeric envelopes were efficiently incorporated into vector particles and could bind to human cells through their displayed antibody fragments, but did not infect them. The spacing between the scFvs and the SU glycoproteins had no significant effect on the efficiency of envelope expression or viral incorporation and did not affect the binding properties of the chimeric envelopes, nor did it influence the efficiency of targeted gene delivery to human cells by scFv-displaying vectors. However, on murine fibroblasts the infectivity of vectors incorporating the chimeric envelopes was strongly influenced by the length of the interdomain spacer. The titers were very low when the single-chain antibodies were fused through a tripeptide linker to SU residue +7 and were greatly enhanced (up to 10(5)-fold) when they were fused to SU residue +1 through a heptapeptide linker. These results point to the importance of steric interactions between the domains of chimeric envelope glycoproteins and may have implications for retroviral vector design for human gene therapy.     

Polymorphism of bacteriophage T7

For viruses made of nucleic acid and protein, the structure of the protein outer shell has, in the past, been found to be uniquely determined by the viral genome. However, here, non-denaturing agarose gel electrophoresis of bacteriophage T7 reveals two states of the mature T7 capsid; the conditions of growth are found to alter the population by T7 of these two electrophoretically defined states. Both states have been previously observed for a genetically altered T7 and they are observed here for wild-type T7. The average electrical surface charge density of a bacteriophage particle (delta) determines its state; the delta of particles in both states is negative. For a given condition of growth, the population of these two states is influenced by the extent to which the major T7 outer shell protein, p10A, is accompanied by its minor readthrough variant, p10B. Comparison of the two electrophoretic states reveals the following. (1) No difference in radius is present in the outer shell (+/-2%). (2) As the pH of electrophoresis is either increased or decreased from neutrality, the state becomes more highly populated for which delta is greater in magnitude (state 1). By changing the pH, some T7 particles are made to change state. (3) Particles in state 1 adsorb less quickly to host cells than do the particles in the alternative state (state 2). This latter observation suggests the hypothesis that state 1 evolved to reduce the probability of re-initiating an infection when conditions are not favorable for growth. This hypothesis is supported by the observation that, as conditions of growth become apparently more unfavorable, progeny increasingly populate state 1.     

Dynamic digital holographic wavelength filtering

This paper describes the theory and results of a new generic technology for use in optical telecommunications and wavelength division multiplexing (WDM): dynamic digital holographic wavelength filtering. The enabling component is a polarization-insensitive ferroelectric liquid crystal (FLC) spatial light modulator (SLM) in conjunction with a highly wavelength-dispersive fixed diffractive element. The technology has been used to perform demultiplexing of single or multiple WDM signals, dynamic erbium doped fiber amplifier (EDFA) gain equalization and channel management, and used to tune an erbium-doped fiber laser (EDFL) functioning as a high power, very narrow linewidth WDM source