Antiferrodistortive reconstruction of the PbTiO(3)(001) surface.

We present in situ x-ray scattering measurements of the surface structures of PbTiO(3) (001) in equilibrium with PbO vapor. At 875 to 1025 K, a reconstruction having c(2x2) symmetry is present under most conditions, while a 1 x 6 reconstruction occurs under PbO-poor conditions. The atomic structure of the c(2x2) phase is found to consist of a single layer of an antiferrodistortive structure with oxygen cages counter-rotated by 10 degrees about the titanium ions.

Cocaine inhibits NGF-induced PC12 cells differentiation through D(1)-type dopamine receptors.

In utero cocaine exposure can adversely affect CNS development. Previous studies showed that cocaine inhibits neuronal differentiation in a dose-dependent fashion in nerve growth factor (NGF)-stimulated PC12 cells. Cocaine binds with high affinity to several neurotransmitter transporters, resulting in elevated neurotransmitter levels in nerve endings. To determine if cocaine inhibits neurite outgrowth through the effects of these neurotransmitters, we applied dopamine, norepinephrine, serotonin, and acetylcholine to NGF-induced PC12 cells. Dopamine was the only neurotransmitter to inhibit neurite outgrowth significantly in a dose-dependent pattern without affecting cell viability. Norepinephrine and acetylcholine did not affect neurite outgrowth, while serotonin enhanced it. Furthermore, GBR 12909, a potent dopamine transporter (DAT) inhibitor, yielded similar effects. We then showed PC12 cells express D(1) and D(2) receptors and DAT proteins. Dopamine uptake measured over time was significantly blocked by cocaine and GBR 12909 which may result in elevated extracellular dopamine. The role of dopamine receptors in PC12 differentiation was further examined by using D(1) and D(2) specific receptor agonists. Only the D(1) agonist, SKF-38393, had a significant dose-dependent inhibitory effect. In addition, a D(1) antagonist produced significant recovery of neurite outgrowth in cocaine-treated cells. These findings suggest that cocaine inhibitory effects on neuronal differentiation are mediated through its binding to the dopamine transporter, resulting in increased dopamine level in the synapses. Subsequently, up regulation of D(1) receptors alters NGF signaling pathways.

Perinatal care: cultural and technical differences between China and the United States.

A comparison of perinatal care in the U.S. and China is presented. Perinatal care has made tremendous achievements in both countries since mid-century. However, the outcomes in the two cultures are different due to the different focus on caring concepts, the strengths of a nursing philosophy, and the emphasis on the nursing role in maternal care. Perinatal family in the U.S. will have advantages in perinatal education physical facilities, and a philosophy of care. North American women have greater access to early prenatal and continuing care, and less infant mortality. Chinese women have less access to qualified nursing services, higher infant mortality rates, and limited perinatal education. Overall, Chinese perinatal care is far behind that which is found in the U.S. This comparison analyzes the strengths and weaknesses in both cultures with a focus on change that will produce healthier and more consistent optimal outcomes.

Cocaine inhibition of neuronal differentiation in NGF-induced PC12 cells is independent of ras signaling.

In utero exposure to cocaine may result in altered neuronal development. Our previous studies demonstrated cocaine inhibits neurite outgrowth in NGF-induced PC12 cells through dopamine, by activation of D1 receptors. This study examined where cocaine interferes in the NGF signaling cascade. GSrasl cells that inducibly express activated forms of Ras upon treatment with dexamethasone were used. Morphological differentiation was quantified by counting cells bearing neurite-like processes after 72 h exposure to either dexamethasone or NGF alone, or with cocaine, dopamine or SKF-38393. Cocaine, dopamine, and the D1 agonist inhibited neurite-like process outgrowth in both dexamethasone and NGF-induced GSras1 cells. GAP-43 expression, used as a measure for biochemical differentiation was severely diminished in NGF and dexamethasone-induced GSras1 cells treated with cocaine. These results suggest that cocaine, dopamine and activation of D1 receptors affect the NGF signaling downstream, independent of ras expression, leading to altered neuronal differentiation.

C-fos mediates cocaine inhibition of NGF-induced PC12 cell differentiation.

In utero cocaine exposure can affect CNS development. Previous studies showed that cocaine inhibits neuronal differentiation in a dose-dependent fashion, in nerve growth factor (NGF)-stimulated PC12 cells, without affecting cell viability. NGF activates intracellular signaling proteins, specific immediate-early genes (IEG) including a transient peak of c-fos expression, and induction of late genes expression, leading to the neuronal phenotype. We hypothesized that cocaine interferes with NGF signaling. Therefore, we examined the pattern of c-fos expression in our cellular model. Time course of c-fos expression up to 72 h was determined in cells treated with NGF 20 ng/ml and cocaine 10 microgram/ml (a moderately toxic level) by RT-PCR analysis. Total RNA was isolated from cells, and levels of c-fos mRNA were estimated using gene-specific primers. In both control and experimental conditions, c-fos level was maximal at 0.5 h. In the control cells, c-fos expression declined rapidly to less than 5% of the 0.5h value, while in the cocaine-treated cells, c-fos level persisted through the 72-h exposure. Adding c-fos antisense to cells treated with NGF and cocaine resulted in significant improvement of neurite out-growth, from 28% (NGF + cocaine) to 89% (NGF + cocaine + c-fos antisense) of control differentiation after 72 h of exposure (Dunnet's T < 3.24). Inhibitory effects of cocaine on NGF-induced PC12 differentiation may be attributed to alteration of c-fos expression. Further studies will be required to examine the role of D1 receptor activation in mediating c-fos expression and to explore the effects of cocaine on other IEGs.

The effects of a multimedia system in supermarkets to alter shoppers' food purchases: nutritional outcomes and caveats.

A randomized-control test of a multimedia nutrition intervention-the Nutrition for a Lifetime System (NLS©)- utilized supermarket receipts to examine effects of NLS treatment on the daily per person nutritional content of participants' supermarket purchases. In regression analyses controlling for background variables, baseline purchases and trends toward increased purchasing, NLS treatment contributed to lower levels of total fat and to higher levels of total fiber and servings of fruits and vegetables at post-test. Redemption of NLS coupons contributed to greater decreases in fat and increases in servings of fruits and vegetables in users' purchases. Implications for future interventions promoting healthier food choices include tailoring program content and addressing broader lifestyle issues such as caloric intake and expenditure.

Patients' health problems: differences in perceptions between home health patients and nurses.

Quality care is consumer-driven care. Yet, much of home healthcare is driven by Medicare regulations and reimbursement rates. This study compared home health patients' perceptions of their health problems with nurses' documentation of the patients' health problems. The results showed that the problems patients report and nurses document are very different. Home health nurses must move beyond a focus on medicare-reimbursable patient problems to documenting and providing consumer-driven patient care.

Inhibitory effects of cocaine on NGF-induced neuronal differentiation: incomplete reversibility after a critical time period.

We extend our findings showing dose-dependent cocaine inhibition of differentiation in NGF-stimulated PC-12 cells without affecting cell viability by demonstrating that neurite extension is severely limited after 24 h, maximal effect is reached at 36 h and recovery is only partial. Cocaine metabolites lack these effects. A similar process may occur following human prenatal exposure, perhaps through cocaine-induced changes in gene expression or other intracellular signalling events.

Novel use of limited primer extension in detecting mutations in human iduronate 2-sulfatase gene.

Hunter syndrome is characterized by a deficiency of iduronate 2-sulfatase. A large number of mutations in the gene have been reported. We describe here the development of a limited primer method for the identification of mutations. In the reaction mixture designed for the limited primer extension, one or two deoxynucleotides from the four necessary deoxynucleotides are added as "selected nucleotides" and another deoxynucleotide which is radiolabeled is added as the "limited nucleotide". The absence of one or two of the deoxynucleotides limits the length of primer elongation, and the low concentration of the "limited nucleotide" causes an "extension-delay" effect and results in a banding pattern upon electrophoresis of the products thus making it possible to distinguish mutant and normal alleles. We have studied three novel mutations in exon IX, 407delTT (TTT to T), 423insCC (CCC to CCCCC), and W502X (TGG to TAG) of the iduronate 2-sulfatase gene by the limited primer extension method.

Heavy metals in seaducks and mussels from misty fjords national monument in Southeast Alaska.

Quartz Hill, in Misty Fjords National Monument near Ketchikan, Alaska, is the site of a proposed molybdenum-producing mine. To provide baseline data for use in post-development comparisons, we analyzed tissues of Barrow's goldeneyes (Bucephala islandica), common mergansers (Mergus merganser), and blue mussels (Mytilus edulis) for seven heavy metals that could potentially be released into the environment as a result of mining operations. Specimens were collected in 1980, 1981, and 1982 from two fjords likely to be used for discharge of tailings from the proposed mine and from two control fjords. Concentrations of arsenic, cadmium, copper, chromium, molybdenum, lead, and zinc were measured in soft tissues of mussels and in kidney, liver, and muscle of birds. The highest mean concentrations of metals found in bird tissues were 55.7 ppm dry weight cadmium in kidneys and 154 ppm dry weight zinc in livers of Barrow's goldeneyes. Concentrations of several metals in blue mussels differed among seasons and locations, but the most significant finding in mussels was a maximum mean cadmium concentration of 9.6 ppm dry weight, a level higher than normally found in undisturbed areas. With the exception of 104 ppm dry weight cadmium in the kidney of one common merganser and 12.7 ppm dry weight lead in the kidney of another, concentrations of other metals in seaduck and mussel tissues were low, consistent with what would be expected for a pre-development environment. Molybdenum was found in low concentrations (<10 ppm dry weight) in all avian kidney samples and most liver samples, but was not detected in blue mussels.

Detection and Characterization of Cocaine and Related Tropane Alkaloids in Coca Leaf, Cocaine, and Biological Specimens.

Cocaine, atropine and scopolamine are the three most important alkaloids in the tropane group. The detection of these alkaloids and their metabolites, at trace levels in biological matrices, is reviewed. These matrices include human and rat physiological fluids such as blood, urine, and saliva as well as human body tissue and hair. The detection, isolation, and determination of cocaine and related tropane alkaloids in cocaine-bearing leaf of South American and greenhouse-cultivated coca is discussed. The relationship between tropane alkaloids in coca leaf and their presence in illicit refined cocaine is addressed. A survey of modern methods for the detection of tropane alkaloids, including mass spectrometry, ultraviolet, infrared and Raman spectroscopy, gas and high-performance liquid chromatography and immunoassay techniques, is presented.

Intimacy and science: the publication of clinical facts in psychoanalysis.

This paper starts by stating that in science there are no facts independent of theory. In psychoanalysis, the theory of the decisive importance of the unconscious makes it possible to grasp clinical facts. This leads to the centrality of transference in analysis. The latter is understood as a social fact. Transference, perceived as a private experience, can be known in the intimacy of the psychoanalytic relationship, through the communication by means of language, which is public. Psychoanalysis is then considered a science of intimacy. The analyst, in publishing clinical facts, faces the problem of the transposition of a fact from the intimacy sphere, considered as private, to the public sphere, and thus serves a scientific purpose. A treatment report is presented to illustrate the problems of the registering, editing and publishing of clinical facts, based on the parallel between making conscious that which is unconscious and making potentially public what is private. Thus the analyst confronts similar difficulties and anxieties, when publishing clinical facts, as the ones that the analysand must overcome to know, through the social experience of psychic intimacy, his or her private inner world.

Choline deficiency in cultured adrenal medullary cells: effect on phosphatidylcholine biosynthesis.

The effect of choline deficiency on the composition and biosynthesis of the major membrane phospholipids was examined in adrenal medullary cells maintained in suspension cultures. The amount and proportions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in these cells were not affected by the removal of choline from the culture media. However, the rate of biosynthesis of choline at the phosphatide level by the stepwise methylation of PE increased twofold within 24 h after choline was removed from the culture media, while ethanolamine incorporation into PE was increased by 50%. In contrast, the rate of incorporation of labeled choline into PC, presumably via CDP-choline, was virtually identical in cells that had been preincubated in the presence or absence of 1 mM choline. These results demonstrate that cultured cells of neural origin are capable of compensating for lack of exogenous choline by forming choline at the phosphatide level through the sequential methylation of PE. The hypolipidemic drug, DH-990, when added to the culture media, inhibited conversion of phosphatidylmonomethylethanolamine (PME) to PC, but had no effect on the N-methylation of PE. This differential effect indicates that the initial N-methylation of PE is catalyzed by an enzyme that is distinguishable from the enzyme(s) catalyzing the conversion of PME to PC.