Cryptosporidium and cryptosporidiosis

Cryptosporidium is one of the most common enteric protozoan parasites of vertebrates with a wide host range that includes humans and domestic animals. It is a significant cause of diarrhoeal disease and an ubiquitous contaminant of water which serves as an excellent vehicle for transmission. A better understanding of the development and life cycle of Cryptosporidium, and new insights into its phylogenetic relationships, have illustrated the need to re-evaluate many aspects of the biology of Cryptosporidium. This has been reinforced by information obtained from the recent successful Cryptosporidium genome sequencing project, which has emphasised the uniqueness of this organism in terms of its parasite life style and evolutionary biology. This chapter provides an up to date review of the biology, biochemistry and host parasite relationships of Cryptosporidium.

Demonstration of a spaser-based nanolaser

One of the most rapidly growing areas of physics and nanotechnology focuses on plasmonic effects on the nanometre scale, with possible applications ranging from sensing and biomedicine to imaging and information technology. However, the full development of nanoplasmonics is hindered by the lack of devices that can generate coherent plasmonic fields. It has been proposed that in the same way as a laser generates stimulated emission of coherent photons, a 'spaser' could generate stimulated emission of surface plasmons (oscillations of free electrons in metallic nanostructures) in resonating metallic nanostructures adjacent to a gain medium. But attempts to realize a spaser face the challenge of absorption loss in metal, which is particularly strong at optical frequencies. The suggestion to compensate loss by optical gain in localized and propagating surface plasmons has been implemented recently and even allowed the amplification of propagating surface plasmons in open paths. Still, these experiments and the reported enhancement of the stimulated emission of dye molecules in the presence of metallic nanoparticles lack the feedback mechanism present in a spaser. Here we show that 44-nm-diameter nanoparticles with a gold core and dye-doped silica shell allow us to completely overcome the loss of localized surface plasmons by gain and realize a spaser. And in accord with the notion that only surface plasmon resonances are capable of squeezing optical frequency oscillations into a nanoscopic cavity to enable a true nanolaser, we show that outcoupling of surface plasmon oscillations to photonic modes at a wavelength of 531 nm makes our system the smallest nanolaser reported to date-and to our knowledge the first operating at visible wavelengths. We anticipate that now it has been realized experimentally, the spaser will advance our fundamental understanding of nanoplasmonics and the development of practical applications.

A multinational phase III randomized trial with or without consolidation chemotherapy using docetaxel and cisplatin after concurrent chemoradiation in inoperable stage III non-small cell lung cancer (CCheIN): Interim analysis

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Background: Currently, the recommended treatment for inoperable stage III non-small cell lung cancer (NSCLC) is concurrent chemoradiotherapy (CCRT). The efficacy of consolidation chemotherapy after CCRT needs to be confirmed. The aim of this phase III randomized trial is to determine the efficacy of consolidation chemotherapy with docetaxel (D) and cisplatin (P) following definitive CCRT with the same agents in stage III inoperable NSCLC. Herein we report the pre-planned interim analysis. Methods: Patients with inoperable stage III NSCLC were randomized to either CCRT alone (observation arm) or CCRT followed by consolidation chemotherapy (consolidation arm). N2 or N3 disease was confirmed by PET and/or pathology. CCRT with D (20 mg/m2) and P (20 mg/m2) was administered every week for 6 weeks with a total dose of 66 Gy of thoracic RT as 33 fractions. In the consolidation arm, patients were further treated with 3 cycles of D and P (35 mg/m2 each on day 1 and 8, every 3 weeks). The primary endpoint is time to progression (TTP). Total target number of patients is 458. Results: From Oct 2005 to Mar 2008, 233 patients were enrolled and 226 were randomized (observation 112; consolidation 114). Patients’ characteristics were similar in both arms. In the consolidation arm, 83 patients (73%) received consolidation chemotherapy, of whom 52 (45%) completed 3 planned cycles. Grade 3–4 neutropenia occurred in 5.4% of 203 consolidation cycles. Common non-hematologic toxicities of all grades during consolidation were anorexia (47%), nausea (37%), vomiting (16%), fatigue (35%) and esophagitis (31%). At the time of this analysis, there were 40 and 41 deaths in the observation and consolidation arms, respectively. Treatment-related mortality rates were similar. With a median follow-up of 28.2 months, the median TTP was 9.0 months in the observation arm and 13.9 months in the consolidation arm (P=0.19). Median overall survival was 20.7 and 21.2 months, respectively (P=0.49). Conclusions: This interim analysis suggests that consolidation chemotherapy with DP after CCRT with weekly DP is feasible and relatively well tolerated. Patient enrollment is ongoing.

No significant financial relationships to disclose.

CTLA4 gene polymorphisms are associated with chronic bronchitis

Chronic obstructive pulmonary disease (COPD) is characterised by chronic and progressive dyspnoea, cough and sputum production. T-lymphocytes may play a key role in the pathogenesis of COPD and chronic bronchitis. Cytotoxic T-lymphocyte antigen (CTLA) 4 is a potential candidate gene because it modulates T-cell activation. Genetic association between nine CTLA4 single nucleotide polymorphisms (SNPs) and chronic bronchitis was assessed in 606 pedigrees (1,896 individuals) from the International COPD Genetics Network (ICGN) population. We then replicated the associations in 342 COPD subjects with chronic bronchitis and 511 COPD subjects without chronic bronchitis from Bergen, Norway. Family-based association tests were used to analyse the ICGN cohort, and a logistic regression model was used for the Bergen cohort. Six CTLA4 SNPs were significantly associated with chronic bronchitis in the ICGN cohort (0.0079< or = p < or =0.0432), with three being replicated with the same directionality of association in the Bergen cohort (0.0325< or = p < or =0.0408). One of these replicated SNPs (rs231775) encodes the Thr to Ala substitution at amino acid position 17. Haplotype analyses supported the results of single SNP analyses. Thus, CTLA4 is likely to be a genetic determinant of chronic bronchitis among COPD cases.

Stimulated emission of surface plasmon polaritons

We have observed laserlike emission of surface plasmon polaritons (SPPs) decoupled to the glass prism in an attenuated total reflection setup. SPPs were excited by optically pumped molecules in a polymeric film deposited on the top of a silver film. Stimulated emission was characterized by a distinct threshold in the input-output dependence and narrowing of the emission spectrum. The observed stimulated emission and corresponding compensation of the metallic absorption loss by gain enables many applications of metamaterials and nanoplasmonic devices.

Elongation of surface plasmon polariton propagation length without gain

We have demonstrated that an addition of highly concentrated rhodamine 6G chloride dye to the PMMA film adjacent to a silver film can cause 30% elongation of the propagation length of surface Plasmon polaritons (SPPs). The possibility to elongate the SPP propagation length without optical gain opens a new technological dimension to low-loss nanoplasmonic and metamaterials.

Single- and two-photon excitation of a GaAs random laser

We have demonstrated an anti-Stokes random laser emission at lambda approximately 885 nm in micrometer-size powder of GaAs. The maximal pumping wavelength, lambda=1,300 nm, exceeded the lasing wavelength by nearly 50%. We conclude that both one- and two-photon pumping contribute to optical excitation of the material, with the two-photon pumping being a key process in creating the population inversion and gain.

Simultaneous Spatial and Temporal Focusing in Nonlinear Microscopy

Simultaneous spatial and temporal focusing (SSTF), when combined with nonlinear microscopy, can improve the axial excitation confinement of wide-field and line-scanning imaging. Because two-photon excited fluorescence depends inversely on the pulse width of the excitation beam, SSTF decreases the background excitation of the sample outside of the focal volume by broadening the pulse width everywhere but at the geometric focus of the objective lens. This review theoretically describes the beam propagation within the sample using Fresnel diffraction in the frequency domain, deriving an analytical expression for the pulse evolution. SSTF can scan the temporal focal plane axially by adjusting the GVD in the excitation beam path. We theoretically define the axial confinement for line-scanning SSTF imaging using a time-domain understanding and conclude that line-scanning SSTF is similar to the temporally-decorrelated multifocal multiphoton imaging technique. Recent experiments on the temporal focusing effect and its axial confinement, as well as the axial scanning of the temporal focus by tuning the GVD, are presented. We further discuss this technique for axial-scanning multiphoton fluorescence fiber probes without any moving parts at the distal end. The temporal focusing effect in SSTF essentially replaces the focusing of one spatial dimension in conventional wide-field and line-scanning imaging. Although the best axial confinement achieved by SSTF cannot surpass that of a regular point-scanning system, this trade-off between spatial and temporal focusing can provide significant advantages in applications such as high-speed imaging and remote axial scanning in an endoscopic fiber probe.

Compensation of loss in propagating surface plasmon polariton by gain in adjacent dielectric medium

We report the suppression of loss of surface plasmon polariton propagating at the interface between silver film and optically pumped polymer with dye. The large magnitude of the effect enables a variety of applications of 'active' nanoplasmonics. The experimental study is accompanied by the analytical description of the phenomenon. In particular, we resolve the controversy regarding the direction of the wavevector of a wave with a strong evanescent component in an active medium.

Sensitized nonlinear emission of gold nanoparticles

We have studied Stokes and anti-Stokes emission of Au nanoparticles suspended in pure methanol and methanol solution of rhodamine 6G dye. In the presence of dye, excitation of anti-Stokes emission of gold involves two-photon absorption in rhodamine 6G molecules followed by the energy transfer to Au nanoparticles with simultaneous absorption of one pumping photon by Au. The sensitization by dye molecules caused six-fold enhancement of the anti-Stokes emission of gold nanoparticles.

Emission of Au nanoparticles with and without rhodamine 6G dye

We have observed Stokes and anti-Stokes emission of Au nanoparticles suspended in methanol and rhodamine 6G dye solution. Photoluminescence of Au nanoparticles is a three-step process involving single-photon or three-photon excitation of electron-hole pairs, relaxation of excited electrons and holes, and emission from electron-hole recombination, possibly enhanced by surface plasmons. In the presence of dye, the excitation of anti-Stokes emission of gold involves two-photon absorption in rhodamine 6G molecules followed by the energy transfer to Au nanoparticles with simultaneous absorption of one pumping photon by Au. This mechanism significantly enhances anti-Stokes emission of gold nanoparticles in the presence of dye.

Association of PTGDR gene polymorphisms with asthma in two Caucasian populations

The prostanoid DP receptor (PTGDR) is shown to be involved in the asthma patho-physiology and the results from the published genetic association studies are inconsistent. Four single nucleotide polymorphisms (SNPs) in PTGDR were genotyped in 342 and 294 families from UK and Denmark respectively. Asthma and asthma-related phenotypes were analyzed using family-based association analyses. In the UK families, a promoter polymorphism (-731A/G) showed significant associations with asthma (P=0.0022), atopic asthma (P=0.0044), bronchial hyperreactivity or BHR (P=0.00120) and strict asthma (P=0.0008). The P-values for asthma, BHR and strict asthma were significant even after the most stringent correction for the number of markers and the number of phenotypes analyzed (<0.0031). An intronic polymorphism (+6651C/T) also showed significant associations with asthma (P=0.0302), atopic asthma (P=0.0131), BHR (P=0.0249) and strict asthma (P=0.0261). In the Danish families, an intronic polymorphism (+6541C/T) showed significant associations with asthma (P=0.0071), atopic asthma (P=0.0348), BHR (P=0.0033) and strict asthma (P=0.0381). The results of haplotype analyses supported the ones of the single SNP analyses. Thus, we demonstrated significant evidence of association between polymorphisms in PTGDR with asthma phenotypes in the two Caucasian populations.

Racial origin is associated with poor awareness of prostate cancer in UK men, but can be increased by simple information

Prostate cancer is the second most common cause of cancer death in UK men. We have shown a higher incidence and disease stage in black British men (unpublished), however there is no evidence regarding their awareness of prostate cancer and screening. We assessed the level of prostate cancer awareness and attitudes in Black and White men in the UK, and to see if written information would modify awareness. Information was collected from two groups of 871 men without prostate cancer using a new, validated, prostate cancer awareness questionnaire. The first group was asked to fill in the questionnaire, whereas the second group was initially given printed information on prostate cancer and requested to fill in the questionnaire. Data were compared between the two ethnic groups using SPSS statistical package. Changes in knowledge and attitudes after providing prostate health education were analysed. There was a significantly lower response from Black men. In the first group, Black men were unaware of their increased risk of developing the disease and demonstrated poor knowledge about the symptoms of prostate cancer (P<0.001) and also more negative attitudes about its control and treatment (P<0.01). In the second group, there were significant improvements in knowledge, risk awareness and attitudes following targeted education: this was true for Black and White men. Although Black British men have a high risk of prostate cancer, their knowledge of the disease is poor. Simple education methods can significantly improve awareness and knowledge in both Black and White men.

Genomewide scans of red cell indices suggest linkage on chromosome 6q23

BACKGROUND

The red cell indices quantify the size, number and oxygen-carrying ability of erythrocytes. Although the genetic basis of many monogenic forms of anaemia is well understood, comparatively little is known about the genes responsible for variation in the red cell indices among healthy participants.

OBJECTIVE

To identify quantitative trait loci (QTLs) responsible for normal variation in the red cell indices of 391 pairs of dizygotic twins who were measured longitudinally at 12, 14 and 16 years of age.

RESULTS

Evidence suggesting linkage of red cell indices to haemoglobin concentration (LOD = 3.03) and haematocrit (LOD = 2.95) on chromosome 6q23, a region previously identified as possibly harbouring a QTL for haematocrit, was found. Evidence for linkage to several other regions of the genome, including chromosome 4q32 for red cell count and 7q for mean cell volume, was also found. In contrast, there was little evidence of linkage to the chromosomal regions containing the genes for erythropoietin (7q21) and its receptor (19p13.2), nor to the regions containing the genes for the haemoglobin alpha (16p13.3) and beta chains (11p15.5).

CONCLUSION

Findings provide additional evidence for a QTL affecting haemoglobin and haematocrit on chromosome 6q23. In contrast, polymorphisms in the genes coding for erythropoietin, its receptor and the haemoglobin alpha and beta chains do not appear to contribute substantially to variation in the red cell indices between healthy persons.

Anomalous intracranial venous drainage associated with basal ganglia calcification

We describe the neuroradiologic findings in a 7-year-old boy with anomalous intracranial venous drainage and cerebral calcification. CT scans demonstrated that his scalp mass was a plexus of scalp veins filled through the emissary foramen, and there were cerebral calcifications. Angiography revealed bilateral sigmoid sinus atresia with most of the intracranial venous drainage via the prominent mastoid emissary veins into dilated scalp vein. The possible relationship between cerebral calcification and anomalous intracranial venous drainage is discussed.

Enhancement of surface plasmons in an Ag aggregate by optical gain in a dielectric medium

We have observed the compensation of loss in a metal by a gain in a dielectric medium in the mixture of an Ag aggregate and a Rhodamine 6G dye. The demonstrated sixfold enhancement of the Rayleigh scattering is the evidence of the enhancement of the surface-plasmon resonance. The reported experimental observation facilitates many applications of nanoplasmonics.

Fibrinogen and von Willebrand factor-independent platelet aggregation in vitro and in vivo

BACKGROUND

Fibrinogen (Fg) has been considered essential for platelet aggregation. However, we recently demonstrated formation of occlusive thrombi in Fg-deficient mice and in mice doubly deficient for Fg and von Willebrand factor (Fg/VWF(-/-)).

METHODS AND RESULTS

Here we studied Fg/VWF-independent platelet aggregation in vitro and found no aggregation in citrated platelet-rich plasma of Fg/VWF(-/-) mice. Surprisingly, in Fg/VWF(-/-) plasma without anticoagulant, adenosine diphosphate induced robust aggregation of Fg/VWF(-/-) platelets but not of beta(3)-integrin-deficient (beta(3) (-/-)) platelets. In addition, beta(3) (-/-) platelets did not significantly incorporate into thrombi in Fg/VWF(-/-) mice. This Fg/VWF-independent aggregation was blocked by thrombin inhibitors (heparin, hirudin, PPACK), and thrombin or thrombin receptor activation peptide (AYPGKF-NH(2)) induced aggregation of gel-filtered Fg/VWF(-/-) platelets in 1 mm Ca(2+) PIPES buffer. Notably, aggregation in PIPES buffer was only 50-60% of that observed in Fg/VWF(-/-) plasma. Consistent with the requirement for thrombin in vitro, hirudin completely inhibited thrombus formation in Fg/VWF(-/-) mice. These data define a novel pathway of platelet aggregation independent of both Fg and VWF. Although this pathway was not detected in the presence of anticoagulants, it was observed under physiological conditions in vivo and in the presence of Ca(2+)in vitro.

CONCLUSIONS

beta(3) integrin, thrombin, and Ca(2+) play critical roles in this Fg/VWF-independent aggregation, and both plasma and platelet granule proteins contribute to this process.

Lycopene inhibits DNA synthesis in primary prostate epithelial cells in vitro and its administration is associated with a reduced prostate-specific antigen velocity in a phase II clinical study

Interest in lycopene has focused primarily on its use in the chemoprevention of prostate cancer (CaP); there are few clinical trials involving men with established disease. In addition, most data examining its mechanism of action have been obtained from experiments using immortal cell lines. We report the inhibitory effect(s) of lycopene in primary prostate epithelial cell (PEC) cultures, and the results of a pilot phase II clinical study investigating whole-tomato lycopene supplementation on the behavior of established CaP, demonstrating a significant and maintained effect on prostate-specific antigen velocity over 1 year. These data reinforce the justification for a large, randomized, placebo-controlled study.

MMP-1 promoter gene polymorphism and susceptibility to chronic periodontitis in a Chinese population

A single nucleotide polymorphism in the promoter region of -1607 bp of the human MMP-1 gene has been found to be associated with an increased risk of various inflammatory diseases and cancer metastasis. This study aimed to evaluate the association between the MMP-1 promoter gene polymorphism and chronic periodontitis susceptibility and/or severity in a Chinese population. Genomic DNA was obtained from whole blood samples in 60 Chinese subjects with chronic periodontitis and 50 periodontally healthy subjects as controls. MMP-1 promoter fragment was amplified by polymerase chain reaction, and the polymorphism was analyzed by restriction endonuclease cleavage. In the control subjects, the 2G allele was observed a frequency of 49%, while in severely diseased patients, the 2G allele was seen in 73.4%. The individuals with the 2G allele seem to be approximately three times at greater risk for developing the severe chronic periodontitis (chi(2) = 12.148, P = 0.000). The genotype of 2G/2G was found in 58.5% of the severe periodontitis and 24% of the control group (chi(2) = 11.779, P = 0.003). This study suggests that a single nucleotide polymorphism in the MMP-1 promoter region of -1607 bp may be associated with severe chronic periodontitis in a Chinese population.

Polyethylene Glycol (Molecular Weight 400 DA) Vehicle Improves Gene Expression of Adenovirus Mediated Gene Therapy

PURPOSE

A significant limitation of adenoviral mediated suicide gene therapy is poor gene distribution in vivo. The choice of vehicle has been demonstrated to affect the level of adenoviral delivered gene transduction. We examined the hypotheses that 1) adenovirus suspended in PEG400 improves gene expression in the naïve canine prostate model, 2) improved transgene expression with PEG400 results in improved tumor control and 3) vehicle affects the initial adenoviral spread from a single intratumor injection.

MATERIALS AND METHODS

The magnitude and volume of gene expression were measured 24 hours following intraprostatic injection of adenovirus suspended in PEG400 (12.5% weight per volume) or saline as vehicle. Tumor growth delay was measured in mice bearing human tumor xenografts following the injection of adenovirus in PEG400 and saline. The initial spread of adenovirus was measured by confocal microscopy following a single injection of fluorescently labeled adenoviral particles in human tumor xenografts using each vehicle.

RESULTS

Adenovirus suspended in PEG400 provided an average of twice the level of gene expression in the canine prostate and significantly better tumor control relative to saline in preclinical tumor models (p = 0.046 and 0.036, respectively). The initial spread of adenovirus with PEG400 was superior to that of adenovirus in saline and the latter was largely limited to the needle tract.

CONCLUSIONS

Adenoviral gene therapy vectors suspended in PEG400 results in improved tumor control because of greater initial adenoviral spread, and the increased volume and magnitude of gene expression in vivo.

Use of expired breath ethanol measurements in evaluation of irrigant absorption during high-power potassium titanyl phosphate laser vaporization of prostate

OBJECTIVES

To evaluate formally the risk and levels of irrigant absorption during high-power potassium titanyl phosphate (KTP) laser vaporization of the prostate by the Greenlight PV system using the expired breath ethanol technique.

METHODS

Forty consecutive patients underwent laser vaporization of the prostate. Of these patients, 17 had a preoperative transrectal ultrasound estimation of the prostate volume (mean 97 cm3). All procedures were performed under general anesthesia, by either of two consultants or a trainee. A 1% ethanol solution was used as irrigation fluid. Throughout the operation, the expired breath was analyzed for ethanol using a standard alcometer "plumbed" into the anesthetic circuit. Venous blood samples were taken immediately before and after the procedure for measurements of serum sodium and plasma alcohol levels.

RESULTS

On average, 155,000 J of laser energy was delivered in 47 minutes. In all patients and on all occasions, the expired breath ethanol remained at 0. No statistically significant change was found in the serum sodium concentration during the procedure (P = 0.42), and no patient displayed any clinical evidence of transurethral resection syndrome.

CONCLUSIONS

The results of this study have confirmed, for the first time, the lack of significant absorption of irrigation fluid during high-power KTP vaporization of the prostate using a recognized sensitive technique and the safety of using sterile water as that irrigant. This was the case even in those patients with very large prostates who are usually considered at high risk of experiencing the clinical consequences of fluid absorption during transurethral resection of the prostate and regardless of the experience of the surgeon.

Photodynamic therapy increases brain edema and intracranial pressure in a rabbit brain tumor model

The objective of this study was to evaluate the effect of a single photodynamic therapy (PDT) on brain edema and intracranial pressure (ICP) in a rabbit model of brain tumor. A total of 57 adult New Zealand rabbits were assigned to 3 groups: the PDT group, the tumor group, and the tumor plus PDT group. Rabbits in the PDT group (n = 9) received PDT but no tumor implantation; rabbits in the tumor group (n = 18) received VX2 carcinoma implantation but no PDT; rabbits in the tumor plus PDT group (n = 30) received tumor implantation with subsequent PDT 16 days later. Brain edema and ICP levels were then evaluated. We found that ICP in the PDT group was 7.43 +/- 0.50 mmHg. After tumor implantation, ICP increased rapidly (18.43 +/- 1.10 mmHg, 21 days later). PDT alone did not increase ICP, but compared with that in the tumor group, ICP increased significantly in the tumor plus PDT group (9.55 +/- 1.32 vs. 13.31 +/- 1.13 mmHg, p < 0.01) 24 hours after treatment. Brain water content in the tumor group increased rapidly after tumor implantation. PDT again increased perineoplastic brain edema 24 hours after treatment (81.09 +/- 0.97% vs. 78.32 +/- 0.49%, p < 0.01). It should be noted that PDT alone did not induce brain edema. In conclusion, PDT causes transient brain edema and increases ICP in a rabbit brain tumor model.

Genome-wide scan of IQ finds significant linkage to a quantitative trait locus on 2q

A genome-wide linkage scan of 795 microsatellite markers (761 autosomal, 34 X chromosome) was performed on Multidimensional Aptitude Battery subtests and verbal, performance and full scale scores, the WAIS-R Digit Symbol subtest, and two word-recognition tests (Schonell Graded Word Reading Test, Cambridge Contextual Reading Test) highly predictive of IQ. The sample included 361 families comprising 2-5 siblings who ranged in age from 15.7 to 22.2 years; genotype, but not phenotype, data were available for 81% of parents. A variance components analysis which controlled for age and sex effects showed significant linkage for the Cambridge reading test and performance IQ to the same region on chromosome 2, with respective LOD scores of 4.15 and 3.68. Suggestive linkage (LOD score>2.2) for various measures was further supported on chromosomes 6, 7, 11, 14, 21 and 22. Where location of linkage peaks converged for IQ subtests within the same scale, the overall scale score provided increased evidence for linkage to that region over any individual subtest. Association studies of candidate genes, particularly those involved in neural transmission and development, will be directed to genes located under the linkage peaks identified in this study.

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.