Enhanced phosphorylation of cyclic AMP response element binding protein in the brain of mice following repetitive hypoxic exposure

Cerebral ischemic/hypoxic preconditioning (I/HPC) is a phenomenon of endogenous protection that renders the brain tolerant to sustained ischemia/hypoxia. This profound protection induced by I/HPC makes it an attractive target for developing potential clinical therapeutic approaches. However, the molecular mechanism of I/HPC is unclear. Cyclic AMP (cAMP) response element binding protein (CREB), a selective nuclear transcriptional factor, plays a key role in the neuronal functions. Phosphorylation of CREB on Ser-133 may facilitate its transcriptional activity in response to various stresses. In the current study, we observed the changes in CREB phosphorylation (Ser-133) and protein expression in the brain of auto-hypoxia-induced HPC mice by using Western blot analysis. We found that the levels of phosphorylated CREB (Ser-133), but not protein expression of CREB, increased significantly (p<0.05) in the hippocampus and the frontal cortex of mice after repetitive hypoxic exposure (H2-H4, n=6 for each group), when compared to that of the normoxic (H0, n=6) or hypoxic exposure once group (H1, n=6). In addition, a significant enhancement (p<0.05) of CREB phosphorylation (Ser-133) could also be found in the nuclear extracts from the whole hippocampus of hypoxic preconditioned mice (H2-H4, n=6 for each group). These results suggest that the phosphorylation of CREB might be involved in the development of cerebral hypoxic preconditioning.

Modulation of cellular response to cisplatin by a novel inhibitor of DNA polymerase beta

DNA polymerase beta (Pol beta) is an error-prone enzyme whose up-regulation has been shown to be a genetic instability enhancer as well as a contributor to cisplatin resistance in tumor cells. In this work, we describe the isolation of new Pol beta inhibitors after high throughput screening of 8448 semipurified natural extracts. In vitro, the selected molecules affect specifically Pol beta-mediated DNA synthesis compared with replicative extracts from cell nuclei. One of them, masticadienonic acid (MA), is particularly attractive because it perturbs neither the activity of the purified replicative Pol delta nor that of nuclear HeLa cell extracts. With an IC50 value of 8 microM, MA is the most potent of the Pol beta inhibitors found so far. Docking simulation revealed that this molecule could substitute for single-strand DNA in the binding site of Pol beta by binding Lys35, Lys68, and Lys60, which are the main residues involved in the interaction Pol beta/single-strand DNA. Selected inhibitors also affect the Pol beta-mediated translesion synthesis (TLS) across cisplatin adducts; MA was still the most efficient. Therefore, masticadienonic acid sensitized the cisplatin-resistant 2008C13*5.25 human tumor cells. Our data suggest that molecules such as masticadienonic acid could be suitable in conjunction with cisplatin to enhance anticancer treatments.

Two brothers with trichiasis, entropion and corneal scarring, sensorineural hearing loss, progressive thinning of scalp hair, mild learning difficulties and distinct facial features. A new syndrome?

Two brothers with very similar phenotypes involving trichiasis (misdirected lashes), entropion with corneal abrasions, strabismus, progressive thinning of the scalp hair, sensorineural hearing impairment, mild learning difficulties, and inguinal hernias are described. They have similar, distinctive facial features with deep-set eyes, a high nasal bridge and a short philtrum. Both brothers are carriers of a maternally inherited apparently balanced translocation of chromosomes 11 and 18: 46,XY, t(11;18)(p13;q21)mat. However, this is thought to be coincidental, since their younger brother also carries this translocation and is phenotypically normal. Although they have many features that are found in the ectodermal dysplasia syndromes, their combination of features is distinct and has to our knowledge not been previously reported.

35ANALYSIS OF EPIGENETIC MODIFICATIONS AND GENOMIC IMPRINTING IN NUCLEAR TRANSFER DERIVED BOS GAURUS×B. TAURUS CONCEPTI

Somatic cell nuclear transfer in cattle is an inefficient process hindered by low pregnancy rates and fetal placental abnormalities. Improper or incomplete epigenetic reprogramming of the donor genome has been implicated as a cause for these aberrations and has been investigated extensively in mice. Here we report the use of a bovine interspecies model (Bos gaurus×B. taurus) for the assessment and characterization of epigenetic modifications and genomic imprinting in 40-day-old female nuclear transfer (NT)-derived fetuses and placentas. Previously, we identified genomic imprinting at the IGF2, GTL2 and XIST loci in the Bos gaurus×B. taurus fetuses. These results indicated maternal and paternal imprinting of the IGF2 and GTL2 loci, respectively, in the chorion, allantois, liver, lung and brain, whereas the XIST locus was maternally imprinted solely in the chorion of females. We extended this analysis to 40-day-old NT fetuses derived from a hybrid lung fibroblast cell line (female). Analysis of the donor cell line indicated conservation of imprinting of the IGF2 and GTL2 loci and bialleic expression of the XIST locus, presumably from the random patterns of X-chromosome inactivation. Analysis of three NT and three control pregnancies indicated disruption of genomic imprinting at the XIST locus in the chorions of all three clones compared to controls. In contrast, proper allelic expression of the IGF2 and GTL2 loci was observed in all fetuses and placentas. Quantification of maternal and paternal XIST transcripts in the chorion of clones and controls demonstrated a significant skewing from preferential paternal expression in controls (95.0±0.882, mean±S.E.) to mixed paternal and maternal expression in clones (73.6±5.2), (t-test; P&lt;0.05). In an attempt to determine the cause for the abnormal allelic expression of the XIST locus in the chorion of the clones, methylation analysis of the XIST Differentially Methylated Region (DMR) was performed. Methylation-sensitive restriction digests and subsequent PCR of the XIST DMR indicated patterns were not different between controls and clones. However, when genome-wide and promoter-specific methylation analysis (bisulfite sequencing) was extended to the satellite I repeat element and epidermal cytokeratin promoter, hypermethylation was observed in the chorion of clones. These results demonstrate disruption of genomic imprinting in XIST locus in the placenta of 40-day-old clones independent of DMR methylation. They also indicate that cloning is associated with increased levels of methylation in selected genomic regions in the chorion.

Dopaminergic drug effects on physiological connectivity in a human cortico-striato-thalamic system

Cortico-striato-thalamic (CST) systems are anatomical substrates for many motor and executive functions and are implicated in diverse neuropsychiatric disorders. Electrophysiological studies in rats, monkeys and patients with Parkinson's disease have shown that power and coherence of low frequency oscillations in CST systems can be profoundly modulated by dopaminergic drugs. We combined functional MRI with correlational and path analyses to investigate functional and effective connectivity, respectively, of a prefronto-striato-thalamic system activated by object location learning in healthy elderly human subjects (n = 23; mean age = 72 years). Participants were scanned in a repeated measures, randomized, placebo-controlled design to measure modulation of physiological connectivity between CST regions following treatment with drugs which served both to decrease (sulpiride) and increase (methylphenidate) dopaminergic transmission, as well as non-dopaminergic treatments (diazepam and scopolamine) to examine non-specific effects. Functional connectivity of caudate nucleus was modulated specifically by dopaminergic drugs, with opposing effects of sulpiride and methylphenidate. The more salient effect of sulpiride was to increase functional connectivity between caudate and both thalamus and ventral midbrain. A path diagram based on prior knowledge of unidirectional anatomical projections between CST components was fitted satisfactorily to the observed inter-regional covariance matrix. The effect of sulpiride was defined more specifically in the context of this model as increased strength of effective connection from ventral midbrain to caudate nucleus. In short, we have demonstrated enhanced functional and effective connectivity of human caudate nucleus following sulpiride treatment, which is compatible both with the anatomy of ascending dopaminergic projections and with electrophysiological studies indicating abnormal coherent oscillations of CST neurons in parkinsonian states.

Neurons in the periaqueductal gray are critically involved in the neuronal network for audiogenic seizures during ethanol withdrawal

The periaqueductal gray (PAG) is implicated in the network subserving audiogenic seizures (AGS). AGS are seen during ethanol withdrawal (ETX), and the present study examined effects of focal NMDA receptor blockade in PAG during ETX and PAG neuronal firing changes associated with ETX. Bilateral cannulae or microwire electrodes were chronically implanted into PAG. Ethanol was administered intragastrically at 8-h intervals for 4 days, resulting in AGS susceptibility during ETX. Microinjection of a competitive NMDA receptor antagonist, DL-2-amino-7-phosphonoheptanoic acid (AP7) (2 and 5 but not 1 nmol/side), into the PAG suppressed AGS, in part, reversibly. In microwire experiments spontaneous and acoustically evoked PAG neuronal responses in behaving rats were reduced significantly 1 h after initial administration of ethanol. During ETX, when the animals were susceptible to AGS, significant increases in spontaneous and acoustically evoked PAG neuronal firing occurred. PAG neurons exhibited burst firing 2-4 s prior to the tonic-clonic phase of AGS and tonic repetitive firing during this seizure phase, which ceased during post-ictal depression. Increased NMDA receptor function in PAG may be important to the aberrant PAG neuronal firing in AGS, since previous studies observed upregulation of NMDA receptors during ETX, and the present study observed that focal microinjection of a NMDA antagonist into PAG blocked AGS.

Neurons in the deep layers of superior colliculus are a requisite component of the neuronal network for seizures during ethanol withdrawal

Ethanol withdrawal (ETX) in ethanol-dependent animals and humans often results in seizure susceptibility. The deep layers of superior colliculus (DLSC) are proposed to be involved in the neuronal networks of several types of seizures. In rodents, ETX results in susceptibility to audiogenic seizures (AGS), and the DLSC are implicated as a critical component of the seizure network in a genetic form of AGS. Ethanol inhibits NMDA receptors, and the binding at these receptors is increased during ETX in certain brain regions. Therefore, the effect of focal microinjection into DLSC of a competitive NMDA receptor antagonist, DL-2-amino-7-phosphonoheptanoic acid (AP7) on ETX seizures was examined. AP7 (2 and 5 nmol/side) microinjected bilaterally into DLSC suppressed AGS, supporting a critical role of the DLSC in the AGS network during ETX. DLSC neuronal firing changes in behaving rats were subsequently examined, using chronically implanted microwire electrodes. Acoustically-evoked DLSC firing was significantly suppressed during ethanol intoxication and during ETX. However, DLSC neurons began firing tonically 1-2 s before the onset of the wild running behavior of AGS. Acoustically-evoked DLSC firing was suppressed during post-ictal depression with recovery beginning as the righting reflex returned. These data support a requisite role of the DLSC in AGS during ETX. These neuronal firing changes suggest an important role of DLSC neurons in generation of the wild running phase of AGS during ETX, which may be a general pathophysiological mechanism and a critical event in the initiation of wild running, since a similar pattern was seen previously in a genetic form of AGS.

Auxin- and abscisic acid-dependent osmoregulation in protoplasts of Phaseolus vulgaris pulvini

Protoplasts isolated from the laminar pulvinus of Phaseolus vulgaris and bathed in a medium containing KCl as the major salt were found to swell in response to IAA and to shrink in response to ABA. The protoplasts of flexor cells and those of extensor cells responded similarly. The results indicate that the cellular content of osmotic solutes is enhanced by IAA and reduced by ABA. The IAA-induced swelling was abolished when either the K(+) or the Cl(-) of the bathing medium was replaced by an impermeant ion or when the medium was adjusted to neutral pH (instead of pH 6). The response was inhibited by vanadate. It is concluded that the swelling is caused by enhanced influxes of K(+) and Cl(-), which probably occur through K(+) channels and Cl(-)/H(+) symporters, respectively. The ABA-induced shrinking was inhibited by 5-nitro-2-(3-phenylpropylamino)-benzoic acid, an anion-channel inhibitor, suggesting that it is caused by Cl(-) efflux through anion channels and charge-balancing K(+) efflux through outward-rectifying K(+) channels. It appears that the two plant hormones act on pulvinar motor cells to regulate their turgor pressure, as they do in stomatal guard cells. The findings are discussed in relation to the pulvinar movements induced by environmental stimuli.

Audiogenic seizure susceptibility is induced by termination of continuous infusion of gamma-aminobutyric acid or an N-methyl-D-aspartic acid Antagonist into the inferior colliculus

The inferior colliculus (IC) is strongly implicated in seizure initiation in a genetic form of audiogenic seizures (AGS) and in AGS observed during ethanol withdrawal (ETX). Ethanol is known to block the actions of excitatory amino acids (EAA) and enhance the actions of gamma-aminobutyric acid (GABA) in several brain areas, including the IC. The present study investigated the effects on susceptibility to AGS following withdrawal from continuous blockade of N-methyl-D-aspartic acid (NMDA) receptors or continuous activation of GABA receptors in the IC. This involved infusion of GABA (1 M) or a competitive NMDA antagonist, DL-2-amino-7-phosphonoheptanoic acid (AP7, 1 mM), at 0.25 microl/h for 7 days using an Alzet osmotic minipump. Following abrupt termination of the infusion, AGS susceptibility began at 30 min. The incidence of AGS was 38.9 and 56.3% following GABA and AP7 withdrawal, respectively. The AGS behaviors observed during withdrawal, which included wild running and bouncing clonus, were very similar to those evoked by acoustic stimuli during ETX. AGS susceptibility lasted for several hours and in 13% of animals persisted for up to 6 months. The current results support diminished GABAergic and elevated glutamatergic function in the IC as the critical mechanisms and sites for AGS initiation. The present study, coupled with previous evidence that chronic ethanol exposure reduced GABA-mediated inhibition and enhanced EAA-mediated excitation, suggests that these amino acid receptor-mediated alterations in the IC are key elements in initiating AGS during ethanol withdrawal.

The preliminary experimental study of induced differentiation of embryonic stem cells into corneal epithelial cells

PURPOSE

To study preliminarily induced differentiation of embryonic stem cells into corneal epithelial cells in vitro.

METHODS

Murine embryonic stem cells were co-cultured with Rabbit limbal corneal epithelial cells in Transwell system to induce differentiation. Mophological and immunohistochemical examination were implemented.

RESULTS

The induced cells from embryonic stem cells have an epithelial appearance. The cells formed a network and were confluent into film gradually after being co-cultured with rabbit limbal corneal epithelial cells for 24-96 hours. The cells ranged mosaic structure and localized together with clear rim. Most of the cells showed polygonal appearance. Transmission electron microscope showed lots of microvilli on the surface of induced cells and tight junctions between them. These epithelial-like cells expressed the corneal epithelial cell specific marker cytokeratin3/cytokeratin12.

CONCLUSION

The potential mechanism of the differentiation of murine embryonic stem cells into corneal epithelial cells induced by limbal corneal epithelial cell-derived inducing activity is to be further verified.

Endotoxin and cytokines alter contractile protein expression in cardiac myocytes in vivo

Release of bacterial endotoxin and cytokines induce cardiac failure during sepsis. We investigated the direct effects of E. coli endotoxin (lipopolysaccharide, LPS) and cytokines induced by LPS on the cardiac myocyte gene program. For in vivo-experiments adult Wistar rats were given 600 microg/day LPS i.v. for 24 h or 7 days. In addition, cultured adult rat cardiac myocytes were treated with LPS, interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNFalpha), interferon-gamma (IFNgamma) or IL-6 for 24 h. mRNA expression was evaluated for cardiac-alpha-actin (cAct), skeletal-alpha-actin (skAct), beta- and alpha-myosin heavy chain (MHC). LPS induced betaMHC-mRNA 3.6-fold and repressed alphaMHC 2.7-fold and cAct 2.5-fold after 24 h in vivo. Up-regulation of betaMHC (3-fold) and repression of cAct (2.5-fold) were still observed after 7 days LPS infusion, whereas alphaMHC-mRNA levels had returned to normal. At the protein level, increased expression of betaMHC by LPS treatment occurred already after 24 h and was maintained thereafter. LPS had no influence on skAct-mRNA. Similar changes in contractile protein mRNA expression were observed in LPS-treated cardiomyocytes in culture, whereas the tested cytokines either activated (IL-1beta, IFNgamma) or repressed (TNFalpha, IL-6) both MHC-isoforms and cAct. In conclusion, LPS and proinflammatory cytokines induce changes in contractile protein expression that may contribute to the acute heart failure observed during endotoxaemia.

Myocardial protection of warm blood cardioplegic induction during cardiopulmonary bypass

In his prospective randomized clinical study, we evaluated the myocardial protection of warm blood cardioplegic induction and cold blood cardioplegic induction, respectively, during cardiopulmonary bypass. Twenty-eight adult patients who underwent valve replacement were randomly divided into two groups: group T (14 cases) received cold (6-8 degrees C) blood cardioplegic induction after ECG showed straight line induced by warm (35-37 degrees C) blood cardioplegia; whereas, group C (14 cases) received cold blood cardioplegic induction only. The effects of myocardial protection of both cardioplegic inductions were evaluated by clinical outcomes, myocardial biochemistry index (cardiac troponin T, cTnT), and myocardial automorphology. The ratio of myocardial auto resuscitation was significantly higher in group T (93%) than that in group C (50%). Only one case in group T (7%) and three cases in group C (21%) needed temporary pacemakers. No case in group T (0%) and five cases (36%) in group C received dopamine. The postoperative mechanical ventilation time and ICU stay time of group T were shorter than those of group C. Myocardial biochemistry indexplasma level of cTnT in group T was lower than that of group C immediately and 6 h after cardiopulmonary bypass. Myocardial morphology-group T had comparably better outcomes than group C. We concluded that warm blood cardioplegic induction during cardiopulmonary bypass, compared with cold blood cardioplegic induction, provides better myocardial protection.

[Determination of phosphocreatine in muscular tissues by high performance liquid chromatography]

The quantitation of energy stores(phosphocreatine, PCr) is of paramount importance in the study of living-tissues metabolism. This is more so in the heart, which depends to a very great extent on an uninterrupted aerobic metabolism to maintain its normal function. Availability of data on myocardial energy stores is, therefore, indispensable for assessing the responses of heart to drugs or stresses such as ischemia and hypoxemia. A simple and rapid method for the determination of phosphocreatine in muscular tissues by RP-HPLC has been developed. The chromatographic conditions were as follows: Zorbax XDB-C18 column(150 mm x 4.6 mm i.d., 5 microns), V(20 mmol/L KH2PO4 and 2 mmol/L tetrabutyl ammonium phosphate): V(acetonitrile) = 96:4(pH 5.8) mobile phase and UV detector at 215 nm. PCr in muscular tissues was extracted with 0.4 mol/L HClO4. The calibration curve showed a good linearity in 5 mg/L-100 mg/L(r = 0.9992). The average recovery was 99.34%. The limit of detection was 2 mg/L. The verified results demonstrated that this method is precise, accurate and can be used for determination of PCr in muscular tissue.

Assessing readiness for death in hospice elders and older adults

BACKGROUND

Readiness for death may affect the quality of the death experience and influence response to treatments. The psychologic vulnerability of the dying person is a major focus of palliative care. Accurate assessment of readiness for death may lead to earlier and more appropriate interventions.

OBJECTIVE

The purpose of this study was to assess the psychometric properties of the revised readiness for death instrument.

METHODS

Using a known groups technique and a cross-sectional study design, the revised instrument was administered to 52 elders in hospice care with a terminal diagnosis and 91 community dwelling adults without a terminal diagnosis.

RESULTS

Instrument content validity (Kappa = 0.96) was supported by three expert panelists who were hospice researchers. Principal components factor analysis explained 43% of the variance and partially supported the proposed four-factor structure of the revised 26-item instrument. Internal consistency was acceptable (.76). Discriminant validity was significant as assessed by an independent t-test between two contrast groups (t = 5.98, p = 0.000). The factor analysis, reliability testing, and qualitative analysis of items supported deletion of 2 items.

CONCLUSIONS

Results indicated that the revised instrument has sound psychometric properties but further testing with a larger sample of hospice subjects is needed to confirm the factor structure of the instrument.

Goal attainment scaling with sexual offenders: a measure of clinical impact at posttreatment and at community follow-up

The impact of cognitive-behavioral interventions was assessed for 28 low-moderate risk and 20 high-risk sexual offenders on conditional release to the Greater Toronto Area. Goal Attainment Scaling (GAS--T. Hogue, 1994) for sexual offenders was used to rate clinical and motivational elements of treatment taken from reports written at pretreatment, posttreatment, and after 3 months of community follow-up. Results indicated that both groups of offenders benefited from treatment, although low-moderate risk offenders showed consistently better results on all measures. Performance along nonrelapse prevention related dimensions increased from pretreatment to posttreatment and remained relatively steady in the community. Relapse prevention related treatment components showed a steady increase from pretreatment throughout follow-up in the community for low-moderate risk offenders, but not for high-risk offenders. Both groups improved substantially in level of motivation from pretreatment to posttreatment; however, only those in the low-moderate risk group maintained their motivation levels once released to the community. These results are discussed with respect to the effectiveness of cognitive-behavioral treatment of sexual offenders.