Dermatitis-inducing furanocoumarins on leaf surfaces of eight species of Rutaceous and Umbelliferous plants

Eight species of Rutaceae or Umbelliferae, known to cause or suspected of causing photophytodermatitis, had the linear furanocoumarins psoralen, bergapten, and xanthotoxin on their leaf surfaces, in concentrations varying from 0.014 to 1800 /gmg/g fresh weight, equivalent to 0.17-56% of the total leaf concentration. The higher percentage generally observed for spring leaves compared to autumn leaves suggests a higher rate of transfer of these furanocoumarins to the surface in the younger leaves. Among the plants studied,Ruta graveolens had the highest surface concentrations of all three furanocoumarins. The relatively high effectiveness in causing dermatitis of some species with low surface concentrations may be explained by a more effective mechanism of transfer of the furanocoumarins to the skin. A role in the defense of the plant is suggested by their accumulation on the plant surface.

Chronopharmacology: new insights and therapeutic implications

Most facets of mammalian physiology and behavior vary according to time of day, thanks to endogenous circadian clocks. Therefore, it is not surprising that many aspects of pharmacology and toxicology also oscillate according to the same 24-h clocks. Daily oscillations in abundance of proteins necessary for either drug absorption or metabolism result in circadian pharmacokinetics, and oscillations in the physiological systems targeted by these drugs result in circadian pharmacodynamics. These clocks are present in most cells of the body, organized in a hierarchical fashion. Interestingly, some aspects of physiology and behavior are controlled directly via a "master clock" in the suprachiasmatic nuclei of the hypothalamus, whereas others are controlled by "slave" oscillators in separate brain regions or body tissues. Recent research shows that these clocks can respond to different cues and thereby show different phase relationships. Therefore, full prediction of chronopharmacology in pathological contexts will likely require a systems biology approach that considers chronointeractions among different clock-regulated systems.

Nominal association with CHRNA4 variants and nicotine dependence

Nicotine binds to nicotinic acetylcholine receptors and studies in animal models have shown that α4β2 receptors mediate many behavioral effects of nicotine. Human genetics studies have provided support that variation in the gene that codes for the α4 subunit influences nicotine dependence (ND), but the evidence for the involvement of the β2 subunit gene is less convincing. In this study, we examined the genetic association between variation in the genes that code for the α4 (CHRNA4) and β2 (CHRNB2) subunits of the nicotinic acetylcholine receptor and a quantitative measure of lifetime DSM-IV ND symptom counts. We performed this analysis in two longitudinal family-based studies focused on adolescent antisocial drug abuse: the Center on Antisocial Drug Dependence (CADD, N = 313 families) and Genetics of Antisocial Drug Dependence (GADD, N = 111 families). Family-based association tests were used to examine associations between 14 single nucleotide polymorphisms (SNPs) in CHRNA4 and CHRNB2 and ND symptoms. Symptom counts were corrected for age, sex and clinical status prior to the association analysis. Results, when the samples were combined, provided modest evidence that SNPs in CHRNA4 are associated with ND. The minor allele at both rs1044394 (A; Z = 1.988, P = 0.047, unadjusted P-value) and rs1044396 (G; Z = 2.398, P = 0.017, unadjusted P-value) was associated with increased risk of ND symptoms. These data provide suggestive evidence that variation in the α4 subunit of the nicotinic acetylcholine receptor may influence ND liability.

NONO couples the circadian clock to the cell cycle

Mammalian circadian clocks restrict cell proliferation to defined time windows, but the mechanism and consequences of this interrelationship are not fully understood. Previously we identified the multifunctional nuclear protein NONO as a partner of circadian PERIOD (PER) proteins. Here we show that it also conveys circadian gating to the cell cycle, a connection surprisingly important for wound healing in mice. Specifically, although fibroblasts from NONO-deficient mice showed approximately normal circadian cycles, they displayed elevated cell doubling and lower cellular senescence. At a molecular level, NONO bound to the p16-Ink4A cell cycle checkpoint gene and potentiated its circadian activation in a PER protein-dependent fashion. Loss of either NONO or PER abolished this activation and circadian expression of p16-Ink4A and eliminated circadian cell cycle gating. In vivo, lack of NONO resulted in defective wound repair. Because wound healing defects were also seen in multiple circadian clock-deficient mouse lines, our results therefore suggest that coupling of the cell cycle to the circadian clock via NONO may be useful to segregate in temporal fashion cell proliferation from tissue organization.

Peripheral circadian oscillators in mammals

Although circadian rhythms in mammalian physiology and behavior are dependent upon a biological clock in the suprachiasmatic nuclei (SCN) of the hypothalamus, the molecular mechanism of this clock is in fact cell autonomous and conserved in nearly all cells of the body. Thus, the SCN serves in part as a "master clock," synchronizing "slave" clocks in peripheral tissues, and in part directly orchestrates circadian physiology. In this chapter, we first consider the detailed mechanism of peripheral clocks as compared to clocks in the SCN and how mechanistic differences facilitate their functions. Next, we discuss the different mechanisms by which peripheral tissues can be entrained to the SCN and to the environment. Finally, we look directly at how peripheral oscillators control circadian physiology in cells and tissues.

Pulmonary pharmacokinetics of tulathromycin in swine. Part I: Lung homogenate in healthy pigs and pigs challenged intratracheally with lipopolysaccharide of Escherichia coli

The objective of the study was to assess the pharmacokinetics of tulathromycin in lung tissue homogenate (LT) and plasma from healthy and lipopolysaccharide (LPS)-challenged pigs. Clinically healthy pigs were allocated to two dosing groups of 36 animals each (group 1 and 2). All animals were treated with tulathromycin (2.5 mg/kg). Animals in group 2 were also challenged intratracheally with LPS from Escherichia coli (LPS-Ec) 3 h prior to tulathromycin administration. Blood and LT samples were collected from all animals during 17-day post-tulathromycin administration. For LT, one sample from the middle (ML) and caudal lobes (CL) was taken. The concentration of tulathromycin was significantly lower in the ML after the intratracheal administration of LPS-E. coli (P < 0.02). In healthy pigs and LPS-challenged animals, the distribution of the drug into the lungs was rapid and persisted at high levels for 17-day postadministration. The distribution of the drug within the lung seems to be homogenous, at least between the middle and caudal lobes within dosing groups. The concentration versus time profile of the drug and pharmacokinetic parameters in two different lung areas (middle and caudal lobe) were consistent within the groups. The clinical significance of these findings is unknown.

Delayed grafting of fetal CNS tissue into chronic compression lesions of the adult cat spinal cord

This review summarizes a series of experiments involving transplants of embryonic feline CNS tissue into chronic compression lesions of the adult cat spinal cord. Fetal spinal cord (FSC), caudal brainstem (BSt), neocortex (NCx) or a combination of either FSC/NCx or FSC/BSt was transplanted as solid pieces or as a suspension of dissociated cells into the developed cystic cavities produced by static-load compression trauma 2-10 weeks prior to grafting. All cats were immunosuppressed with cyclosporin A and their locomotor function was assessed for 6-30 weeks. Following the period of evaluation, all recipients were perfused with fixative and tissue specimens, taken at the transplantation site, were processed for general histological and/or immunocytochemical analysis. Viable graft tissue was found in all animals with the exception of two cats which showed active rejection of their transplants. All of the viable intraspinal grafts were extensively vascularized and did not show any signs of imminent or on-going tissue rejection. Fetal cat CNS grafts showed an extended maturational phase in that features of immature neural tissue (e.g. a paucity of myelination) were still seen even 6-9 weeks after transplantation. By 20-30 weeks, FSC and BSt grafts had attained a more advanced stage of maturation. Transplants in these chronic lesions were extensively blended with both the gray and white matter of the host spinal cord and could be visualized by magnetic resonance imaging (MRI). MRI could also detect regions of cavitation at the graft-host interface, as well as within some transplants. While preliminary evidence from behavioral studies suggest that the FSC and BSt grafts may improve or spare locomotor function in some recipients, a more rigorous analysis of post-grafting locomotor function is required to determine conclusively the functionality of these transplants.

An acute reversible experimental model of pneumonia in pigs: time-related histological and clinical signs changes

The objective of this study was to evaluate the long-term survival rates, clinical response, and lung gross and microscopic changes in pigs treated intratracheally with lipopolysaccharide of Escherichia coli 0111:B4 (LPS-Ec). Healthy pigs were randomly allocated to three groups: (i) no-LPS-Ec (n=1), (ii) LPS-Ec-T1 (1 mg/mL, 10 mL/pig) (n=7), and (iii) LPS-Ec-T2 (0.5 mg/mL, 10 mL/pig) (n=6). Two pigs from each dose group were euthanized at 24 (n=3 for T1), 48 and 144 h post-LPS-Ec challenge. LPS-Ec-treated animals showed macroscopic lesions in middle lobes of the lung. A reversible recruitment of macrophages and neutrophils was observed at 24, 48, and 144 h post-LPS-Ec challenge. The highest cellular infiltration level was observed at 24 h after challenge. The highest clinical scores were evident in both experimental dose levels within 3 and 5 h after LPS-Ec administration. Administration of LPS-Ec, under the conditions evaluated, can be used to induce a reproducible model of acute pulmonary inflammation in pigs.

(Re)inventing the circadian feedback loop

For 20 years, researchers have thought that circadian clocks are defined by feedback loops of transcription and translation. The rediscovery of posttranslational circadian oscillators in diverse organisms forces us to rethink this paradigm. Meanwhile, the original "basic" feedback loops of canonical circadian clocks have swelled to include dozens of additional proteins acting in interlocked loops. We review several self-sustained clock mechanisms and propose that minimum requirements for diurnal timekeeping might be simpler than those of actual free-running circadian oscillators. Thus, complex mechanisms of circadian timekeeping might have evolved from random connections between unrelated feedback loops with independent but limited time-telling capability.

Aging and circadian disruption: causes and effects

The relationship between aging and daily “circadian” behavior in humans is bidirectional: on the one hand, dysfunction of circadian clocks promotes age-related maladies; on the other, aging per se leads to changes and disruption in circadian behavior and physiology. For the latter case, recent research suggests that changes to both homeostatic and circadian sleep regulatory mechanisms may play a role. Could hormonal changes be in part responsible?

Circadian rhythms. A new histone code for clocks?

A histone-modifying protein drives circadian clocks in an unexpected way.

Fractal electronic devices: simulation and implementation

Many natural structures have fractal geometries that exhibit useful functional properties. These properties, which exploit the recurrence of patterns at increasingly small scales, are often desirable in applications and, consequently, fractal geometry is increasingly employed in diverse technologies ranging from radio antennae to storm barriers. In this paper, we explore the application of fractal geometry to electrical devices. First, we lay the foundations for the implementation of fractal devices by considering diffusion-limited aggregation (DLA) of atomic clusters. Under appropriate growth conditions, atomic clusters of various elements form fractal patterns driven by DLA. We perform a fractal analysis of both simulated and physical devices to determine their spatial scaling properties and demonstrate their potential as fractal circuit elements. Finally, we simulate conduction through idealized and DLA fractal devices and show that their fractal scaling properties generate novel, nonlinear conduction properties in response to depletion by electrostatic gates.

The circadian clock starts ticking at a developmentally early stage

Although overt diurnal rhythms of behavior do not begin until well after birth, molecular studies suggest that the circadian clock may begin much earlier at a cellular level: mouse embryonic fibroblasts, for example, already possess robust clocks. By multiple criteria, we found no circadian clock present in mouse embryonic stem cells. Nevertheless, upon their differentiation into neurons, circadian gene expression was observed. In the first steps along the pathway from ES cells to neurons, a neural precursor cell (NPC) line already showed robust circadian oscillations. Therefore, at a cellular level, the circadian clock likely begins at the very earliest stages of mammalian development.

Systemic and cellular reflections on ageing and the circadian oscillator: a mini-review

From circulation to digestion to excretion, a circadian clock synchronizes most aspects of mammalian physiology with the solar day. During normal ageing, this daily coordination gradually erodes, and during pathological ageing such erosion is exacerbated. Recent experiments suggest that therapies aimed at sustaining circadian function increase quality of life in elderly patients. Hence, a better understanding of the interactions between the circadian clock and ageing - at both cellular and systemic levels - could lead to direct benefits for aged individuals.

Absence of IL-23p19 in donor allogeneic cells reduces mortality from acute GVHD

The p19 dimer of interleukin 23 (IL-23) has been reported to have a major role in the pathogenesis of many experimental and clinical autoimmune diseases and may also have a prominent role in transplantation. We reasoned that deficiency of p19 in the allogeneic donor transplant might reduce the inflammation caused by acute GVHD (aGVHD). The major histocompatibility complex-2 (H2(d)) BALB/c mice were subjected to 8.5 Gy TBI, followed by transplantation with 10 x 10(6) BM and 2.5 x 10(6) spleen cells from H2(d) BALB/c, H2(b) C57Bl/6 (B6) or H2(b) p19-/- donors. In all, 75% of the p19-/- transplanted mice survived, compared with only 12.5% of the B6 transplanted mice. This superior survival is correlated with significantly less severe aGVHD, absence of p19 after transplantation, less upregulation of mRNA and lower serum levels of IL-17 as compared with the B6 transplants. TBI alone significantly upregulated transforming growth factor-beta (TGF-beta), IL-6 and p19 mRNA levels in host BALB/c mice, possibly providing the milieu to induce IL-17 in p19-/- donor cells. IL-22, another cytokine, the induction of which in T-helper 17 (Th17) cells is supported by p19, was upregulated in BALB/c hosts but not in transplanted B6 or p19 donor cells, and may not have had a major role in modifying aGVHD.

Pharmacokinetics of intravenous ceftiofur sodium and concentration in body fluids of foals

The objectives of this study were to determine pharmacokinetics of intravenous (i.v.) ceftiofur in foals, to compare ultra-high performance liquid chromatography tandem mass spectometry (UPLC-MS/MS) and microbiologic assay for the measurement of ceftiofur concentrations, and to determine the minimum inhibitory concentration (MIC) of ceftiofur against common equine bacterial pathogens. In a cross-over design, ceftiofur sodium was administered i.v. to six foals (1-2 days-of-age and 4-5 weeks-of-age) at dosages of 5 and 10 mg/kg. Subsequently, five doses of ceftiofur were administered i.v. to six additional foals between 1 and 5 days of age at a dose of 5 mg/kg q 12 h. Concentrations of desfuroylceftiofur acetamide (DCA), the acetamide derivative of ceftiofur and desfuroylceftiofur-related metabolites were measured in plasma, synovial fluid, urine, and CSF by use of UPLC-MS/MS. A microbiologic assay was used to measure ceftiofur activity for a subset of plasma samples. Following i.v. administration of ceftiofur at a dose of 5 mg/kg to 1-2 day-old foals, DCA had a t(1/2) of 7.8 +/- 0.1 h, a body clearance of 74.4 +/- 8.4 mL/h/kg, and an apparent volume of distribution of 0.83 +/- 0.09 L/kg. After multiple i.v. doses at 5 mg/kg, DCA concentrations in CSF were significantly lower than concurrent plasma concentrations. Ceftiofur activity using a microbiologic assay significantly underestimated plasma concentrations of DCA. The MIC of ceftiofur required to inhibit growth of 90% of isolates of Escherichia coli, Pasteurella spp, Klebsiella spp, and beta-hemolytic streptococci was <0.5 microg/mL. Intravenous administration of ceftiofur sodium at the rate of 5 mg/kg every 12 h would provide sufficient coverage for the treatment of susceptible bacterial isolates.

The size dependence of tin oxide atomic cluster nanowire field effect transistors

Tin oxide (SnO(2)) cluster nanowires have been fabricated using atomic clusters as building blocks. Nanowires with widths of less than 100 nm were defined using electron beam lithography followed by deposition of Sn clusters which were subsequently thermally oxidized. The cluster nanowires were used to fabricate field effect transistors. The transistors were n-type and demonstrated a clear size-dependent behaviour. With zero gate bias the narrowest wires were depleted, both the carrier concentration and the conduction quickly increasing with wire width. This behaviour is attributed to the formation of a surface depletion region caused by Fermi level pinning. The width of the depletion region was estimated using the carrier concentration calculated from the transistor threshold voltages. The change in the wire conductance with UV illumination was also investigated. Illumination with 365 nm light increases the conduction by up to 40 times. This is attributed to a combination of an increase in carriers due to photo-desorption of oxygen from the surface of the wires and an increase in the mobility due to a reduction of inter-grain potential barrier height.

[Significance of opioid receptors in regulation of cardiac tolerance in pathogenic impact of long-term ischemia-reperfusion in vivo]

The study aimed at investigation of the role of opioid receptor (OR) in regulation of cardiac tolerance to ischemia-reperfusion. Opioid receptor ligands and inhibitors were administered in vivo prior to coronary artery occlusion (45 min) and reperfusion (2 hrs). Occurring infraction size/area at risk (IS/AAR) ratio was determined. Pretreatment with the micro-OR agonists DAMGO and dermorphin H exerted no effect on the IS/AAR ratio. Activation of delta 1-OR by DPDPE did not alter cardiac tolerance in ischemia-reperfusion either. Pretreatment with the delta 2-OR agonists deltorphin D and deltorphin E or ORL1 receptor agonist nociceptin exerted no effect on the IS/AAR ratio. Stimulation of K-OR by selective agonists did not modify cardiac tolerance to ischemia-reperfusion. The delta 2-OR agonist deltorphin II significantly reduced the IS/AAR index. This effect was prevented by treatment with naltrexone, naloxone methiodide and the delta 2-OR antagonist naltriben but not by the delta 1-OR antagonist BNTX. The infarction-limiting effect of deltorphin II was also abolished by inhibition of protein kinase C (PKC) and mitochondrial Katp channels. Thus, the agonists of micro, delta 1, kappa, and ORL1 receptors in used doses did not affect cardiac tolerance in ischemia-reperfusion injury in vivo. The peripheral delta 2-OR activation induces infarction size reduction. Its infarction-reducing effect of deltorphin II is mediated via PKC activation and mitochondrial Katp, channel opening.

Perceptions of health and health service utilization among homeless and housed psychiatric consumer/survivors

Homelessness has a direct impact on health. Homeless individuals report several barriers to accessing health care. Although research exists regarding the utilization of health services for homeless and housed psychiatric consumer/survivors, few studies have compared the perceived health and service utilization of these two groups. The objective of this study was to determine whether or not differences exist between the utilization of health services and the perceptions of health of homeless and housed psychiatric consumer/survivors in London, Ontario, Canada. It was hypothesized that differences would exist between homeless and housed psychiatric consumer/survivors on all health-related variables examined. A secondary analysis of quantitative data was conducted in a Community-University Research Alliance on Mental Health and Housing project funded by the Social Sciences and Humanities Research Council of Canada. Key findings include significant differences in the characteristics of each population, the use of health services and their perceptions of health. Implications for practice and policy are discussed.

The association between maternal smoking in pregnancy, other early life characteristics and childhood vision: the Twins Eye Study in Tasmania

PURPOSE

To investigate the association between maternal smoking in pregnancy, early-life environment and childhood vision.

METHODS

Twin and triplet children enrolled in the Twins Eye Study in Tasmania underwent a comprehensive ophthalmic examination and their parents/guardians retrospectively answered a questionnaire regarding crawling, walking and other measures. A subset of these twins was also in the Tasmanian Infant Health Survey, which prospectively collected data on antenatal smoking, gestation, birth weight and other factors.

RESULTS

The mean age of the 346 individuals (172 multiple birth sets) at the time of examination was 9.25+/-2.4 years. Mean unaided visual acuity was 0.0 (6/6). The mean spherical equivalent was +0.87D, and decreased with increasing child age (p<0.01). A prospective analysis, accounting for birth set clustering and relevant confounders, showed increasing levels of maternal smoking in the third trimester was associated with poor stereoacuity on the Titmus test (worse (>) than 100'', p=0.05) and Lang test (p=0.001) and also with the presence of esotropia (p=0.02). These associations persisted after adjustment for infant postnatal smoke exposure at one month of age. Poor stereoacuity on Titmus stereo test circles was associated with late age of first crawling (RR=1.23 (1.06, 1.42) p=0.005 per month) and late age of first walking (RR 1.18 (1.05, 1.22) p=0.001 per month).

CONCLUSIONS

Antenatal smoking was independently associated with poor stereovision and the presence of esotropia. Poor stereoacuity may be associated with delayed age at first crawling or walking.