Influence of pharmacological education on perceptions, attitudes and use of dietary supplements by medical students.

BACKGROUND: The ready availability and use of dietary supplements (DS) by the public means that healthcare professionals require education in this area. In the Republic of Serbia, education related to use of DS is included in undergraduate medical training and it is therefore important to assess the effectiveness of this education. The aim of our survey was to investigate the influence of pharmacological education on the use, attitudes and perceptions of risks associated with DS among medical students. METHODS: Medical students at the University of Kosovska Mitrovica participated in the survey. Three hundred eighty questionnaires were distributed, yielding a response rate of 89% (n = 334). Data were categorized by year of study, completion of a one-year course in pharmacology and having passed the final exam. The results were compared between 192 (58%) medical students educated in pharmacology (MSEP) and 142 (42%) medical students not educated in pharmacology (MSNEP). The questionnaire was divided into 4 parts: socio-demographic and lifestyle/behavioral characteristics, use of DS, attitudes about efficacy, safety and perception of risk due to DS use. Chi-square test, Student's t-test, and Mann-Whitney U test were used for statistical analysis. RESULTS: About 53% of respondents used some form of DS. Attitudes regarding the safety of DS consumption showed a difference between the groups. MSEP were more likely to agree that DS have the potential to cause adverse reactions (Likert scale mean 4.1 vs. 3.5, p < 0.001) as well as interactions with conventional drugs (Likert scale mean 4.2 vs. 3.2, p < 0.001) than MSNEP. Finally, MSEP ranked St. John's wort and ginkgo as the most dangerous DS, but creatine and vitamin C were both ranked as relatively safe. Conversely, MSNEP considered ginkgo and vitamin C the most harmful DS, claiming that omega-3 fatty acids and vitamin D had the least hazardous side effects. CONCLUSION: Our results showed that pharmacological education gives young medical students a better understanding of the risks of DS-drug interactions and potential adverse effects. However, their overall attitudes and perception of risk indicate the need for further education.

Atomically Precise Lateral Modulation of a Two-Dimensional Electron Liquid in Anatase TiO2 Thin Films.

Engineering the electronic band structure of two-dimensional electron liquids (2DELs) confined at the surface or interface of transition metal oxides is key to unlocking their full potential. Here we describe a new approach to tailoring the electronic structure of an oxide surface 2DEL demonstrating the lateral modulation of electronic states with atomic scale precision on an unprecedented length scale comparable to the Fermi wavelength. To this end, we use pulsed laser deposition to grow anatase TiO2 films terminated by a (1 × 4) in-plane surface reconstruction. Employing photostimulated chemical surface doping we induce 2DELs with tunable carrier densities that are confined within a few TiO2 layers below the surface. Subsequent in situ angle-resolved photoemission experiments demonstrate that the (1 × 4) surface reconstruction provides a periodic lateral perturbation of the electron liquid. This causes strong backfolding of the electronic bands, opening of unidirectional gaps and a saddle point singularity in the density of states near the chemical potential.

Momentum-Resolved Electronic Structure of the High-T_{c} Superconductor Parent Compound BaBiO_{3}.

We investigate the band structure of BaBiO_{3}, an insulating parent compound of doped high-T_{c} superconductors, using in situ angle-resolved photoemission spectroscopy on thin films. The data compare favorably overall with density functional theory calculations within the local density approximation, demonstrating that electron correlations are weak. The bands exhibit Brillouin zone folding consistent with known BiO_{6} breathing distortions. Though the distortions are often thought to coincide with Bi^{3+}/Bi^{5+} charge ordering, core level spectra show that bismuth is monovalent. We further demonstrate that the bands closest to the Fermi level are primarily oxygen derived, while the bismuth 6s states mostly contribute to dispersive bands at deeper binding energy. The results support a model of Bi-O charge transfer in which hole pairs are localized on combinations of the O 2p orbitals.

Tailoring the nature and strength of electron-phonon interactions in the SrTiO3(001) 2D electron liquid.

Surfaces and interfaces offer new possibilities for tailoring the many-body interactions that dominate the electrical and thermal properties of transition metal oxides. Here, we use the prototypical two-dimensional electron liquid (2DEL) at the SrTiO3(001) surface to reveal a remarkably complex evolution of electron-phonon coupling with the tunable carrier density of this system. At low density, where superconductivity is found in the analogous 2DEL at the LaAlO3/SrTiO3 interface, our angle-resolved photoemission data show replica bands separated by 100 meV from the main bands. This is a hallmark of a coherent polaronic liquid and implies long-range coupling to a single longitudinal optical phonon branch. In the overdoped regime the preferential coupling to this branch decreases and the 2DEL undergoes a crossover to a more conventional metallic state with weaker short-range electron-phonon interaction. These results place constraints on the theoretical description of superconductivity and allow a unified understanding of the transport properties in SrTiO3-based 2DELs.

In situ investigation of the early stage of TiO2 epitaxy on (001) SrTiO3.

We report on a systematic study of the growth of epitaxial TiO(2) films deposited by pulsed laser deposition on Ti-terminated SrTiO(3) (001) single crystals. By using in situ reflection high energy electron diffraction, low energy electron diffraction, x-ray photoemission spectroscopy, and scanning probe microscopy, we show that the stabilization of the anatase (001) phase is preceded by the growth of a few nanometers thick pseudomorphic Sr(x)TiO(2+y) (x, y < 1) intermediate layer. The data demonstrate that the formation of this intermediate phase is related to the activation of a long range Sr migration from the SrTiO(3) substrate into the film. Our results enrich the phase diagram of the Sr-Ti-O system under epitaxial strain opening a route for the study of the electronic and dielectric properties of the reported Sr-deficient SrTiO(3) phase.

Heat-stress induced synthesis of chloroplast protein synthesis elongation factor (EF-Tu) in a heat-tolerant maize line.

A heat-tolerant maize (Zea mays L.) line, ZPBL 1304, synthesizes a unique set of five heat-shock polypeptides of 45 kDa. Previous studies suggested that these polypeptides might play a role in the development of thermotolerance in maize (Ristic et al., 1996, J. Plant Physiol. 149:424-432; Ristic et al., 1998, J. Plant Physiol. 153:497-505). In the present study, we isolated these polypeptides, sequenced them, and investigated their subcellular distribution and origin. Of the five polypeptides of 45 kDa, three polypeptides, including the two most abundant ones, yielded amino acid sequences similar to the chloroplast and bacterial protein synthesis elongation factor (EF-Tu). This was further confirmed using an antibody raised against maize EF-Tu, which showed a very strong reaction with the 45-kDa heatshock protein(s). Studies on subcellular distribution and origin revealed that the 45-kDa polypeptides were localized to the chloroplasts, and were likely of nuclear origin. A full-length maize EF-Tu cDNA (Zmeftu1), previously isolated from the B73 line of maize, was used as a probe for northern blot analysis of RNA extracted from the ZPBL 1304 maize line (the nucleotide and deduced amino acid sequences of Zmeftu1 are 88% identical to the rice EF-Tu sequence). Northern blots showed a 1.85-fold increase in steady-state levels of EF-Tu mRNA during heat stress. An increase in EF-Tu transcript levels during heat stress was accompanied by increased levels of the EF-Tu protein. Isolated chloroplasts from heat-stressed plants also had higher levels of EF-Tu as compared to control chloroplasts. The maize EF-Tu polypeptides showed > 80% sequence similarity with the bacterial EF-Tu, which has recently been shown to function as a molecular chaperone and to play a role in the protection of other proteins from thermal denaturation (Caldas et al., 1998, J. Biol. Chem. 273:11478-11482). It is hypothesized that chloroplast EF-Tu of the ZPBL 1304 maize line plays an important role in the development of thermotolerance.

Ivermectin for treatment of generalized demodicosis in dogs.

OBJECTIVE: To evaluate the efficacy of daily administration of ivermectin in the treatment of dogs with amitraz-resistant generalized demodicosis. DESIGN: Prospective, clinical trial. ANIMALS: Twelve privately owned dogs with juvenile-onset or adult-onset generalized demodicosis that had failed to respond to biweekly or weekly applications of 0.025% amitraz solution. PROCEDURE: All dogs were treated with undiluted ivermectin at a dosage of 0.6 mg/kg of body weight, PO, every 24 hours. There was no other parasiticidal agent given topically or systemically. A physical examination and multiple skin scrapings were performed every 2 to 4 weeks while dogs were receiving ivermectin. Skin scrapings were performed at approximately the same sites at every examination. After no mites were seen, treatment was continued for at least 2 more weeks and then stopped. Dogs were reexamined, and skin scrapings were repeated if any skin lesions developed. For dogs that remained clinically normal, follow-up information was obtained by telephone. Dogs that were free of clinical signs of demodicosis 12 months after ivermectin administration was discontinued were considered cured. RESULTS: Ten of 12 dogs were cured. Median duration of treatment for these dogs was 10 weeks (range, 6 weeks to 5 months). Two dogs were failures, relapsing 10 months and 11.5 months after treatment was stopped. One of these dogs was successfully treated with a second course of ivermectin. Mild ivermectin toxicosis developed in 1 dog after 6 weeks of treatment; side effects resolved shortly after the treatment was stopped. CLINICAL IMPLICATIONS: Daily use of ivermectin, at a dosage of 0.6 mg/kg, PO, was found to be effective in the treatment of generalized demodicosis in dogs.

Response of Xylem Ray Parenchyma Cells of Red Osier Dogwood (Cornus sericea L.) to Freezing Stress (Microscopic Evidence of Protoplasm Contraction).

Freezing behavior of wood tissue of red osier dogwood (Cornus sericea L.) cannot be explained by current concepts of freezing resistance. Previous studies indicated that water in wood tissue presumably froze extracellularly. However, it was observed that xylem ray parenchyma cells within these tissues could survive temperatures as low as -80[deg]C and the walls of these cells did not collapse during freezing (S.R. Malone and E.N. Ashworth [1991] Plant Physiol 95: 871-881). This observation was unexpected and is inconsistent with the current hypothesis of cell response during freezing. Hence, the objective of our study was to further examine the mechanism of freezing resistance of wood tissue of red osier dogwood. We studied freezing stress response of xylem ray parenchyma cells of red osier dogwood using freeze substitution and transmission electron microscopy. Wood samples were collected in winter, spring, and summer of 1992. Specimens were cooled from 0[deg]C to -60[deg]C at 5[deg]C/h. Freezing stress did not affect the structural organization of wood tissue. However, the xylem ray parenchyma cells showed two unique responses to a freezing stress: protoplasm contraction and protoplasm fragmentation. Protoplasm contraction was evident at all freezing temperatures and in tissues collected at different times of the year. Cells with fragmented protoplasm, however, were noticed only in tissues collected in spring and summer. Protoplasm contraction in winter tissue occurred without apparent damage to the protoplasm. In contrast, protoplasm contraction in spring and summer tissues was accompanied by substantial damage. No evidence of intracellular ice formation was observed in parenchyma cells exposed to freezing stress. Differences in protoplasm contraction and appearance of cells with fragmented protoplasm likely indicated seasonal changes in cold hardiness of the wood tissue of red osier dogwood. We speculate that the appearance of fragmented protoplasm may indicate that cells are being injured by an alternative mechanism in spring and summer.

Ultrastructural Evidence That Intracellular Ice Formation and Possibly Cavitation Are the Sources of Freezing Injury in Supercooling Wood Tissue of Cornus florida L.

Although cellular injury in some woody plants has been correlated with freezing of supercooled water, there is no direct evidence that intracellular ice formation is responsible for the injury. In this study we tested the hypothesis that injury to xylem ray parenchyma cells in supercooling tissues is caused by intracellular ice formation. The ultrastructure of freezing-stress response in xylem ray parenchyma cells of flowering dogwood (Cornus florida L.) was determined in tissue prepared by freeze substitution. Wood tissue was collected in the winter, spring, and summer of 1992. Specimens were cooled from 0 to -60[deg]C at a rate of 5[deg]C h-1. Freezing stress did not affect the structural organization of wood tissue, but xylem ray parenchyma cells suffered severe injury in the form of intracellular ice crystals. The temperatures at which the ice crystals were first observed depended on the season in which the tissue was collected. Intracellular ice formation was observed at -20, -10, and -5[deg]C in winter, spring, and summer, respectively. Another type of freezing injury was manifested by fragmented protoplasm with indistinguishable plasma membranes and damaged cell ultrastructure but no evidence of intracellular ice. Intracellular cavitation may be a source of freezing injury in xylem ray parenchyma cells of flowering dogwood.

Heat Shock Proteins in Two Lines of Zea mays L. That Differ in Drought and Heat Resistance.

Synthesis of heat shock proteins (HSPs) in the leaves of a drought- and heat-resistant (line ZPBL 1304), and a drought- and heat-sensitive (line ZPL 389) line of maize (Zea mays L.) was studied under two environmental stress treatments: (a) soil drying and high temperature and (b) high temperature. In the first treatment 13-day-old plants were exposed to 7-day soil drying followed by high temperature stress (45 degrees C), and in the second treatment 20-day-old plants were exposed to high temperature stress (45 degrees C). Second leaves were labeled with [(35)S]methionine. During the labeling period line ZPBL 1304 showed no signs of leaf dehydration under soil drying and high temperature stress conditions. In contrast, line ZPL 389 was dehydrated 23%, as determined by relative water content. Incorporation of [(35)S]methionine into protein was greater in the resistant than in the sensitive line in both treatments. The pattern of synthesis of HSPs in the two lines was similar in treatments 1 and 2. Both lines synthesized a high molecular mass set and a low molecular mass set of HSPs. Proteins from both sets from both lines of maize appeared similar to each other, with respect to the molecular mass. Heated plants of the drought- and heat-resistant line ZPBL 1304 synthesized a band of HSP(s) of approximately 45 kilodaltons which was not found in heated plants of the drought and heat sensitive line ZPL 389. This is the first report on qualitative intraspecific difference in the synthesis of HSPs in maize.