Linkage Analyses of Event-Related Potential Slow Wave Phenotypes Recorded in a Working Memory Task

Working memory is an essential component of wide-ranging cognitive functions. It is a complex genetic trait probably influenced by numerous genes that individually have only a small influence. These genes may have an amplified influence on phenotypes closer to the gene action. In this study, event-related potential (ERP) phenotypes recorded during a working-memory task were collected from 656 adolescents from 299 families for whom genotypes were available. Univariate linkage analyses using the MERLIN variance-components method were conducted on slow wave phenotypes recorded at multiple sites while participants were required to remember the location of a target. Suggestive linkage (LOD > 2.2) was found on chromosomes 4, 5, 6, 10, 17, and 20. After correcting for multiple testing, suggestive linkage remained on chromosome 10. Empirical thresholds were computed for the most promising phenotypes. Those on chromosome 10 remained suggestive. A number of genes reported to regulate neural differentiation and function (i.e. NRP1, ANK3, and CHAT) were found under these linkage peaks and may influence the levels of neural activity occurring in individuals participating in a spatial working-memory task.

Biphasic actions of topiramate on monoamine exocytosis associated with both soluble N-ethylmaleimide-sensitive factor attachment protein receptors and Ca(2+)-induced Ca(2+)-releasing systems

To explore the pharmacological mechanisms of topiramate (TPM), we determined the effects of TPM on monoamine (dopamine and serotonin) exocytosis associated with N-ethylmaleimide-sensitive factor attachment protein receptors and Ca(2+)-induced Ca(2+)-releasing systems, including inositol-triphosphate receptor and ryanodine receptor in freely moving rat pre-frontal cortex using in vivo microdialysis. During resting stage, Ca(2+) output from endoplasmic reticulum Ca(2+) store via inositol-triphosphate receptor regulates syntaxin-associated monoamine exocytosis mechanism, whereas during neuronal hyperexcitable stage, Ca(2+) output via ryanodine receptor regulates synaptobrevin-associated monoamine exocytosis mechanism. Basal monoamine releases were increased and decreased by therapeutically relevant and supratherapeutic concentration of TPM, respectively. The therapeutic-relevant concentration of TPM increased Ca(2+)-evoked release concentration-dependently; however, its stimulatory effect was attenuated in the supratherapeutic range. The K(+)-evoked releases were reduced by TPM concentration-dependently (from therapeutic to supratherapeutic ranges). The therapeutic-relevant concentration of TPM-induced elevation of basal release was reduced by cleavage with syntaxin and inhibition of inositol-triphosphate receptor predominantly, by cleavage with SNAP-25 and synaptobrevin weakly, but not by ryanodine receptor inhibitor. The therapeutic-relevant concentration of TPM-induced elevation of Ca(2+)-evoked release was reduced by cleavage with syntaxin and inositol-triphosphate receptor inhibitor selectively. The therapeutic-relevant concentration of TPM-induced reduction of K(+)-evoked monoamine release was abolished by cleavage with synaptobrevin, but was not affected by cleavage with SNAP-25 or synaptobrevin. The stimulatory effect of ryanodine receptor agonist on K(+)-evoked monoamine release was reduced by TPM, whereas that of inositol-triphosphate receptor agonist was not affected by TPM. Therefore, these results indicate that the combination of the effects of TPM on exocytosis mechanisms associated with SNARE and Ca(2+)-induced Ca(2+)-releasing systems, enhancement of inositol-triphosphate receptor/syntaxin and inhibition of ryanodine receptor/synaptobrevin in pre-frontal cortex, may be involved in clinical actions of TPM.

Optimization of the transport mean free path and the absorption length in random lasers with non-resonant feedback

We have studied numerically the optimal range of the transport mean free path lt and the absorption length (at the pumping wavelength) la, which minimize the threshold and maximize the slope efficiency of a random laser with non-resonant feedback. The results of the calculations are in a good agreement with the experimental results obtained in the GaAs/Al2O3 random laser.

Regeneratively stabilized 4th order rational harmonic mode-locked erbium doped fiber laser operating at 40Gb/s

We report a long term stabilized 4th order rational harmonic mode-locked (RHML) erbium doped fiber laser operating at 40Gb/s. The cavity length drift induced laser instability is overcomed by constructing a modified regenerative type feedback loop to actively adjust the modulation frequency of the 10GHz driving signal. The 4th RHML fiber laser is tested to be highly stable against environmental perturbations.

Dispersion effects on the detuning properties of actively harmonic mode-locked fiber lasers

Detuning properties for actively harmonic mode-locked fiber lasers has been studied both theoretically and experimentally while taking into account of finite cavity dispersions. The theoretical work is based on the self- consistent time domain circulating pulse method. By keeping terms which are usually neglected in previous studies, we have derived an analytic formula which can predict the saturation behavior associated with large modulation frequency detuning. It is found that for the case of medium cavity dispersion, both the pulse-modulator RF phase lag and the optical carrier frequency of the circulating pulse will change significantly as a function of the modulation frequency detuning. The analytical results are supported by both the numerical simulations as well as the experimental measurements. Our theory can potentially serve as a design guidance for cavity length feedback control of harmonic mode-locked fiber lasers.

A major quantitative trait locus for CD4-CD8 ratio is located on chromosome 11

CD4-CD8 ratio is an important diagnostic measure of immune system functioning. In particular, CD4-CD8 ratio predicts the time taken for progression of HIV infection to acquired immune deficiency syndrome (AIDS) and the long-term survival of AIDS patients. To map genes that regulate differences between healthy individuals in CD4-CD8 ratio, we typed 757 highly polymorphic microsatellite markers at an average spacing of approximately 5 cM across the genome in 405 pairs of dizygotic twins at ages 12, 14 and 16. We used multipoint variance components linkage analysis to test for linkage between marker loci and CD4-CD8 ratio at each age. We found suggestive evidence of linkage on chromosome 11p in 12-year-old twins (LOD=2.55, P=0.00031) and even stronger evidence of linkage in the same region at age 14 (LOD=3.51, P=0.00003). Possible candidate genes include CD5 and CD6, which encode cell membrane proteins involved in the positive selection of thymocytes. We also found suggestive evidence of linkage at other areas of the genome including regions on chromosomes 1, 3, 4, 5, 6, 12, 13, 15, 17 and 22.

80Gb/s clock recovery with phase locked loop based on LiNbO3 modulators

In this paper, we present a scheme for extracting a 10GHz clock from the 80Gb/s optical time division multiplexed (OTDM) return to zero (RZ) data stream. The proposed clock recovery is based on the offset locking technique. By using the input data composed of a repeating "10100000" pattern, residue jitter free operation for clock recovery is demonstrated. The method utilizes a LiNbO3 Mach-Zehnder (MZ) intensity modulator for cross-correlation detections.

Striate palmoplantar keratoderma arising from desmoplakin and desmoglein 1 mutations is associated with contrasting perturbations of desmosomes and the keratin filament network

BACKGROUND

Several hereditary human diseases are now known to be caused by distinct mutations in genes encoding various desmosome components. Although the effects of some of these mutant genes have been analysed by targeted disruption experiments in mouse models, little is known about the cell and tissue changes in affected human patients.

OBJECTIVES

To investigate the effects of heterozygous nonsense mutations in desmoplakin (Dp) and desmoglein (Dsg) 1 which cause the autosomal dominant disorder striate palmoplantar keratoderma (SPPK), focusing on changes in desmosome structure and composition and the associated keratin intermediate filament (KIF) network in palm skin, and in cultured keratinocytes generated from the same site.

METHODS

We analysed palm and nonpalm skin sections from four SPPK patients with Dp mutations and one patient with a Dsg1 mutation with respect to tissue and subcellular morphologies, and correlated the in vivo and in vitro findings.

RESULTS

Using electron microscopy, we found abnormalities of desmosomes and cell-cell adhesion in the suprabasal layers in the epidermis from patients with both Dsg1- and Dp-associated SPPK. These changes were more advanced in skin from patients with Dp mutations. Both Dp and Dsg1 mutations were accompanied by significantly reduced numbers of desmosomes in the suprabasal layers, while decreased desmosome size was evident only in Dsg1-associated SPPK. Confocal microscopy analysis showed marked differences in the expression of keratins and of desmosome components, both between the two types of SPPK, and between SPPK and normal skin. The expression of keratins K5, K14 and K10 was reduced in Dsg1-associated SPPK skin, whereas perinuclear aggregation of keratin filaments was more evident in Dp-associated SPPK. In both types of SPPK upregulation of K16 was pronounced and involucrin labelling was abnormal.

CONCLUSIONS

Mutations in Dp and Dsg1 genes causing SPPK may be associated with perturbations in epidermal differentiation accompanied by a marked disruption of several components of the epidermal scaffold including desmosomes and the KIF network.

Effects of dopamine receptor D4 variation on alcohol and tobacco use and on novelty seeking: multivariate linkage and association analysis

The dopamine D4 receptor gene contains a polymorphic sequence consisting of a variable number of 48-base-pair (bp) repeats, and there have been a number of reports that this polymorphism is associated with variation in novelty seeking or in substance abuse and addictive behaviors. In this study we have assessed the linkage and association of DRD4 genotype with novelty seeking, alcohol use, and smoking in a sample of 377 dizygotic twin pairs and 15 single twins recruited from the Australian Twin Registry (ATR). We found no evidence of linkage or association of the DRD4 locus with any of the phenotypes. We made use of repeated measures for some phenotypes to increase power by multivariate genetic analysis, but allelic effects were still non-significant. Specifically, it has been suggested that the DRD4 7-repeat allele is associated with increased novelty seeking in males but we found no evidence for this, despite considerable power to do so. We conclude that DRD4 variation does not have an effect on use of alcohol and the problems that arise from it, on smoking, or on novelty seeking behavior.

[Detection of DNA of Toxoplasma gondii in rat by using polymerase chain reaction]

OBJECTIVE

To study the significance of DNA of Toxoplasma gondii in peripheral blood.

METHODS

DNA of T. gondii in peripheral blood of 50 infected rats was detected by polymerase chain reaction. A pair of primers was designed, according to the sequence P30 gene specific to T. gondii, to amplify DNA from T. gondii by PCR.

RESULTS

The primers amplified DNA specifically from T. gondii and could not amplify DNA from humans, uninfected rat and mouse and from Trichomonas vaginalis and Entamoeba histolytica. DNA of two Toxoplasma parasites was detected by 35 cycles of amplification, indicating a fair sensitivity of the PCR system.

CONCLUSION

PCR may have a value for early diagnosis of T. gondii infection in rat.

[Sulfation of polysaccharides isolated from Indocalamus tesselatus and their anticytopathic effect on human immunodeficiency virus type I]

For preparation of sulfated polysaccharides isolated from bamboo leaves (Indocalamus tesselatus) with chlorosulfonic acid-pyridine, the experimental conditions as the molar ratio of reactants and temperature and time of reaction were discussed. A homogeneous sulfation method with good yield of more than 80% was obtained and the sufur content was found to be 21.9%. Conformation change in sulfated polysaccharide with changes of intrinsic viscosity, polarimetery and CD spectra were found to be related to the negative charge. The polysaccharide sulfates were shown to have better activity to inhibit cytopathic effect of human immunodeficiency virus(HIV) infection than native polysaccharides. The effective concentration was 10 micrograms.ml-1 while the cytotoxic concentration was 2.5 mg.ml-1.

[Relationship between serum 1,25-dihydroxyvitamin D and bone loss in postmenopausal women]

OBJECTIVE

To study the correlations between loss of activity and/or amont of serum 1,25-dihydroxyvitamin D(1,25(OH)2D) and 25-dihydroxyvitamin D(1,25(OH)2D) and bone loss in postmenopausal women, in order to reveal the possible pathophysiology of postmenopausal osteoporosis.

METHODS

The serum levels of 1,25 (OH)2D, 25 (OH) D, PTH, and E2 in 57 postmenopausal women with osteoporosis and 37 postmenopausal women without osteoporosis were measured by radioimmunology. Their Dpd/Cr in urine was measured by ELISA. The bone mineral density (BMD) at lumbar spine (L2-4) was measured in each subject by DEXA.

RESULTS

The serum 1,25(OH)2D in postmenopausal oeteoporotic women and non-osteoporotic women were 18 pg/ml +/- 6 pg/ml and 31 pg/ml +/- 14 pg/ml respectively (P < 0.01) The serum 25 (OH)2D in postmenopausal oeteoporotic women and non-osteoporotic women were 32 ng/ml +/- 9 ng/ml and 46 ng/ml +/- 17 ng/ml respectively (P < 0.01). Postmenopausal osteoporotic women had a lower estrogen concentration (P < 0.01), higher serum parathyroid hormone (PTH) (P < 0.01) and higher urinary Dpd/Cr level (P < 0.01). The level of serum 1,25(OH)2D was highly correlated with BMD in L2-4 for postmenopausal women (r = 0.693, P < 0.001). There was a close relationship between the serum level of 1,25(OH)2D and serum level of 25(OH)2D, suggesting an association between the two factors.

CONCLUSION

The lower bone mass density was associated with lower level of serum 1,25-dihydroxyvitamin D, accompanied by reduced serum estrogen and elevated serum PTH in postmenopausal women. Those may be among the important pathphysiological changes of postmenopausal osteoporosis.

The dynamics of bone marrow stromal cells in the proliferation of multipotent hematopoietic progenitors by substance P: an understanding of the effects of a neurotransmitter on the differentiating hematopoietic stem cell

Communication within the hematopoietic-neuroendocrine-immune axis is partly mediated by neurotransmitters (e.g. substance P, SP) and cytokines. SP mediates neuromodulation partly through the stimulation of bone marrow (BM) progenitors. This study shows that SP, through the neurokinin-1 receptor, stimulates the proliferation of primitive hematopoietic progenitors: cobblestone-forming cells (CAFC, CD34+). This effect is optimal when macrophage is included within the fibroblast support. Indirect induction of IL-1 could be important in the proliferation of CAFC colonies by SP. Phenotypic and functional studies suggest that SP might directly interact with the CD34+/CD45(dim) population. These studies indicate that SP can initiate a cascade of biological responses in the BM stroma and stem cells to stimulate hematopoiesis.

Role of beta-adrenoceptor at different stages of bronchial asthma

OBJECTIVE

To investigate the changes of beta-adrenergic receptor (beta AR) in peripheral lymphocytes and beta 2AR mRNA levels at different stages of bronchial asthma.

METHODS

beta 2AR density and beta 2AR mRNA level in peripheral lymphocytes, cAMP and cGMP levels in blood plasma were estimated by radioligand binding assay, radioimmunoassay and RT-PCR.

RESULTS

(1) Maximum bound volume (Bmax) and equilibrium dissociation constant (Kd) of beta 2AR of lymphocyte in asthma patients at remission stage were markedly higher than that in normal subjects, while cAMP levels in blood plasma showed no difference. Bmax of beta 2AR and cAMP levels in asthma patients at acute exacerbation stage were significantly lower than that in normal subjects, and Kds between these two groups were not much different. (2) Expression of beta 2ARmRNA in peripheral lymphocytes of asthmatics at remission stage was not significantly different compared with that in normals.

CONCLUSIONS

Amount and function of beta AR and beta 2ARmRNA levels are related to asthmatic conditions. Changes of beta AR and beta 2ARmRNA in asthma might rather be a pathological change accompanied by the course of the disease than a primary defect.

A simulation study on the topotactic transformations from aluminophosphate AlPO(4)-21 to AlPO(4)-25

Aluminophosphate AlPO(4)-21 (AWO), formulated /(CH(3))(2)NH(2)/[Al(3)P(3)O(12)(OH)], has been synthesized solvothermally by using dimethylamine as the template. Single-crystal X-ray diffraction analysis shows that AlPO(4)-21 crystallizes in the monoclinic space group P2(1)/n with a = 8.687(2) A, b = 17.428(5) A, c = 9.159(2) A, beta = 109.60(2) degrees, V = 1306.3(5) A(3), and Z = 4. XRD analysis shows that AlPO(4)-21 transforms to AlPO(4)-25 (ATV) upon calcination at 500 degrees C. The molecular dynamics simulation approach was used to investigate the topotactic transformations from AlPO(4)-21. The simulation study suggests that AlPO(4)-21 is energetically favored to transform to AlPO(4)-25, as well as other hypothetical forms, by the changing of the UUDD chains to the UDUD chains.

[Pulmonary surfactant impairment in the development of ventilator-induced lung injury in rats]

OBJECTIVE

To evaluate whether pulmonary surfactant (PS) impairment plays a role in the development of ventilator-induced lung injury (VILI).

METHODS

Thirty-two healthy adult Sprague-Dawley rats were randomly allocated to four groups ( n = 8, each group ) and mechanically ventilated (MV). (1) P7 group: with settings [expressed as peak inspiratory pressure (PIP, cm H2O)/frequency (cpm)/inspiratory:expiratory ratio/positive end expiratory pressure (PEEP, cm H2O)] of 7/40/1:1/0, (2) P45 group: with settings of 45/ 20/1:1/0, (3) PS group: 100 mg/kg of a porcine PS administered intra-tracheally and with the same settings as P45 group, (4) PEEP group: with settings of 45/20/1: 1/10. After 20 minutes of MV, all animals were killed. Another 8 animals were killed immediately after surgical procedure to serve as nonventilated controls (CON group). Arterial blood O2 partial pressure (PaO2) and maximum thorax-lung compliance (C(max)) were measured, and total proteins (TP), total phospholipids (TPL), small and large aggregates (SA, LA), and minimum surface tension (ST min) of bronchoalveolar lavage fluid (BALF) were analyzed.

RESULTS

P45 group had decreased PaO2, C(max), TPL/TP all P < 0.01), increased TP, SA/LA and ST min of ABLF (all P < 0.01) as compared with P7 group. Both PS group and PEEP group had improved PaO2, C(max), BALF analyses as compared with P45 group (P < 0.05 or P < 0.01). There was no significant difference between P7 group and CON group in any parameter described above.

CONCLUSIONS

A short period of mechanical ventilation with high PIP alone can cause VILI in rats that is associated with PS impairment; both exogenous PS and PEEP can restore or preserve alveolar space PS composition and function, attenuate abnormalities of lung oxygenation and mechanics, indicating PS impairment may play an important role in the development of VILI.