DNA microarray analysis of cyanobacterial gene expression during acclimation to high light

DNA microarrays bearing nearly all of the genes of the unicellular cyanobacterium Synechocystis sp PCC 6803 were used to examine the temporal program of gene expression during acclimation from low to high light intensity. A complete pattern is provided of gene expression during acclimation of a photosynthetic organism to changing light intensity. More than 160 responsive genes were identified and classified into distinct sets. Genes involved in light absorption and photochemical reactions were downregulated within 15 min of exposure to high light intensity, whereas those associated with CO(2) fixation and protection from photoinhibition were upregulated. Changes in the expression of genes involved in replication, transcription, and translation, which were induced to support cellular proliferation, occurred later. Several unidentified open reading frames were induced or repressed. The possible involvement of these genes in the acclimation to high light conditions is discussed.

Is it important to perform pollen skin prick tests in the season?

BACKGROUND

Seasonal exposure to pollens causes the characteristic symptoms of respiratory allergy as well as an increase in specific IgE levels and inflammatory mediator release. However, little is known about the effect of natural allergen exposure on the skin test reactivity of patients with seasonal allergy.

OBJECTIVE

The aim of this study was to investigate the monthly variation in skin test reactions with pollen allergens during pollen season and its relation to pollen counts.

METHODS

Fifteen subjects with seasonal allergic rhinitis and/or asthma (4 male, 11 female) between the ages of 13 and 52 (mean 33.9 +/- 2.9) who lived in Ankara, Turkey were selected for this study. Patients were monitored from the beginning of March to the end of September 1997, and skin prick tests were performed using 5 grass, 12 tree, and 5 weed pollen allergen extracts every month. Atmospheric pollen grains were counted in the Ankara area between January and December, 1997.

RESULTS

There were small but statistically significant increases in tree pollen-induced wheal sizes in May when compared with other months (P < 0.05). Skin test reactivity was correlated with tree pollen counts (r = 0.978, P < 0.05). There was not a significant difference in skin test reactivity to grass and weed pollens between months.

CONCLUSIONS

Although skin test reactivity may be slightly greater to tree pollen during the tree pollen season, the timing of skin testing is not a critical determinant in patients with pollen allergy.

Macrostructural EEG characterization based on nonparametric change point segmentation: application to sleep analysis

In the present investigation a new methodology for macrostructural EEG characterization based on automatic segmentation has been applied to sleep analysis. A nonparametric statistical approach for EEG segmentation was chosen, because it minimizes the need for a priori information about a signal. The method provides the detection of change-points i.e. boundaries between quasi-stationary EEG segments based on the EEG characteristics within four fundamental frequency bands (delta, theta, alpha and beta). Polysomnographic data of 18 healthy subjects were analyzed. Our findings show that nonparametric change-point segmentation in combination with cluster analysis enables us to obtain a clear picture of the hierarchical macrostructural organization of sleep, which is impossible to deduce from the unsegmented EEG data. Analysis of correlations between classically defined sleep stages and piecewise stationary power step functions reveals that three basic patterns can be distinguished: SWS (stage III/stage IV), stage II and stage I/REM. In accordance with correlation analyses, cluster detection shows that the cyclic sleep patterns during the course of the night become clearly observable by implementation of only three classes. Since the described methodology is based on a minimum of a priori assumptions, it may be useful for the development of a new sleep classification standard, which goes beyond the established Rechtschaffen and Kales scheme.

Observation of chaotic and regular dynamics in atom-optics billiards

We report on experimental observations of chaotic and regular motion of ultracold atoms confined by a billiard-shaped optical dipole potential induced by a rapidly scanning laser beam. To investigate the dynamics of the atoms confined by such an "atom-optics" billiard we measure the decay of the number of trapped atoms through a hole on the boundary. A fast and purely exponential decay, the clear signature of chaotic motion, is found for a stadium billiard, but not for a circular or an elliptical billiard, in agreement with theory. We also investigated the effects of decoherence, velocity spread, and gravity on regular and chaotic motion.

Living under a "dormant" canopy: a molecular acclimation mechanism of the desert plant Retama raetam

Desert plants are exposed to a combination of environmental stress conditions, including low water availability, extreme temperature fluctuations, high irradiance and nutrient deprivation. Studying desert plants within their natural habitat may therefore reveal novel mechanisms and strategies that enable plants to resist stressful conditions. We studied the acclimation of Retama raetam, an evergreen stem-assimilating desert plant, to growth within an arid dune ecosystem. Retama raetam contained two different populations of stems: those of the upper canopy, exposed to direct sunlight, and those of the lower canopy, protected from direct sunlight. During the dry season, stems of the upper canopy contained a very low level of a number of essential proteins, including the large and small subunits of rubisco, ascorbate peroxidase and the D1 subunit of the reaction centre of photosystem II. However, RNA encoding these proteins was present; cytosolic transcripts were associated with polysomes, while chloroplastic transcripts were not. Upon water application, as well as following the first rainfall of the season, these "photosynthetically suppressed" stems recovered and accumulated essential proteins within 6-24 h. In contrast, stems of the lower canopy contained the essential proteins throughout the dry season. We suggest that R. raetam uses an acclimation strategy of "partial plant dormancy" in order to survive the dry season. "Dormancy", as evident by the post-transcriptional suppression of gene expression, as well as the suppression of photosynthesis, was induced specifically in stems of the upper canopy which protect the lower canopy by shading.

Acousto-optic scanning system with very fast nonlinear scans

A very fast (>100 kHz) acousto-optic scanning system, which relies on two counterpropagating acoustic waves with the same frequency modulation, is proposed and experimentally demonstrated. This scheme completely suppresses linear frequency chirp and thus permits very fast nonlinear scans and nonconstant linear scans. By changing the phase between the modulating signals, this scheme also provides very fast longitudinal scans of the focal point.

Perfectionism in anorexia nervosa: variation by clinical subtype, obsessionality, and pathological eating behavior

OBJECTIVE

The purpose of this study was to examine the role of perfectionism as a phenotypic trait in anorexia nervosa and its relevance across clinical subtypes of this illness.

METHOD

The Multidimensional Perfectionism Scale and the perfectionism subscale of the Eating Disorder Inventory were administered to 322 women with a history of anorexia nervosa who were participating in an international, multicenter genetic study of anorexia nervosa. All participants were additionally interviewed with the Yale-Brown Obsessive Compulsive Scale and the Yale-Brown-Cornell Eating Disorder Scale. Mean differences on dependent measures among women with anorexia nervosa and comparison subjects were examined by using generalized estimating equations.

RESULTS

Persons who had had anorexia nervosa had significantly higher total scores on the Multidimensional Perfectionism Scale than did the healthy comparison subjects. In addition, scores of the anorexia subjects on the Eating Disorder Inventory-2 perfectionism subscale exceeded Eating Disorder Inventory-2 normative data. For the anorexia nervosa participants, the total score on the Multidimensional Perfectionism Scale and the Eating Disorder Inventory-2 perfectionism subscale score were highly correlated. Total score on the Multidimensional Perfectionism Scale was also significantly related to the total score and the motivation-for-change subscale score of the Yale-Brown-Cornell Eating Disorder Scale.

CONCLUSIONS

These data show that perfectionism is a robust, discriminating characteristic of anorexia nervosa. Perfectionism is likely to be one of a cluster of phenotypic trait variables associated with a genetic diathesis for anorexia nervosa.

Ticlopidine, Alka-Seltzer, or a combination of citric acid with aspirin: effects on platelet aggregation in individuals with an insufficient response to aspirin alone

Aspirin (ASA) does not effectively lower platelet aggregation in all people. The platelet aggregation (PA) score is an easily used clinical method for measuring the effect in individuals of antiplatelet medications. Fifteen apparently healthy subjects (2 men and 13 women), selected for their resistance to ASA's antiaggregation effect, completed a sequential trial of ticlopidine, Alka-Seltzer, and ASA + citric acid (CTA). Ticlopidine was the strongest aggregation inhibitor and the ASA + CTA combination was more inhibitory than Alka-Seltzer. It was determined that measuring antiaggregation effects of a particular agent in an individual prior to usage would optimize treatment. The PA score methodology provides a means for testing patients prior to antiplatelet therapy for prevention and treatment of the thrombotic complications of vascular disease.

Temperament and character in women with anorexia nervosa

The present study examined temperament differences among anorexia nervosa (AN) subtypes and community controls, as well as the effect of body weight on personality traits in women with AN. Temperament and Character Inventory (TCI) scores were compared between 146 women with restrictor-type AN (RAN), 117 women with purging-type AN (PAN), 60 women with binge/purge-type AN (BAN), and 827 community control women (CW) obtained from an archival normative database. Women with AN scored significantly higher on harm avoidance and significantly lower on cooperativeness than CW. Subtype analyses revealed that women with RAN and PAN reported the lowest novelty seeking, RAN women the highest persistence and self-directedness, and PAN women the highest harm avoidance. Body mass index had a nominal effect on subgroup differences, suggesting that personality disturbances are independent of body weight. Findings suggest that certain facets of temperament differ markedly between women with AN, regardless of diagnostic subtype, and controls. More subtle temperament and character differences that were independent of body weight emerged that distinguish among subtypes of AN.

Pharmacotherapy for obsessive-compulsive disorder

SSRIs and the tricyclic antidepressant clomipramine are the first-line therapies for patients with OCD, with the side-effect profile of SSRIs being more favorable than that of clomipramine. As many as 40% to 60% of patients with OCD may not respond to adequate trials of SRIs. Not all patients tolerate SSRIs, and delays in full therapeutic responses often occur. Thus, other pharmacologic approaches to treating patients with OCD have been investigated. Augmentation and monotherapy have been explored with serotonergic enhancers, dopamine and 5-HT antagonists, enhancers of second-messenger systems, and GABAergic agents with varying efficacy.

Fluvoxamine augmentation of antipsychotics improves negative symptoms in psychotic chronic schizophrenic patients: a placebo-controlled study

The efficacy and safety of adding fluvoxamine to antipsychotic treatment in schizophrenic patients with mixed positive and negative symptoms was examined. Fifty-three patients selected for persistent negative and positive symptoms who were receiving antipsychotic treatment were randomly allocated to additional fluvoxamine (50-100 mg/day) or placebo in a double-blind manner. Fluvoxamine was associated with significant improvement in negative symptoms (Scale for the Assessment of Negative Symptoms) compared to placebo. The combination was well tolerated. Fluvoxamine augmentation of antipsychotics is safe in chronic schizophrenic patients with mixed positive and negative symptoms and may ameliorate negative symptoms in such patients.

Spontaneous symmetry breaking and switching in planar nonlinear optical antiwaveguides

We consider guided light beams in a nonlinear planar structure described by the nonlinear Schrodinger equation with a symmetric potential hill. Such an "antiwaveguide" (AWG) structure induces a transition from symmetric to asymmetric modes via a transcritical pitchfork bifurcation, provided that the beam's power exceeds a certain critical value. It is shown analytically that the asymmetric modes always satisfy the Vakhitov-Kolokolov (necessary) stability criterion; nevertheless, the application of a general Jones' theorem shows that the AWG modes are always unstable. To realize the actual character of the instability, we perform direct numerical simulations, which reveal that a deflecting instability, which drives the asymmetric beam into the cladding without giving rise to fanning or stripping of the beam, sets in after a propagation distance of approximately 16 transverse widths of the AWG's core. The symmetry-breaking bifurcation, in combination with the deflecting instability, may be used to design an all-optical switch. The switching can easily be controlled by means of a symmetry-breaking "hot spot" that acts upon an initial symmetric beam launched with a power exceeding the bifurcation value.

Pneumococcal and influenza immunization and human immunodeficiency virus load in children

OBJECTIVE

HIV-infected children receiving influenza vaccine, pneumococcal vaccine and both vaccines concurrently were studied to examine the effect of immunization on plasma HIV viral load.

METHODS

Thirteen children received immunizations: pneumococcal vaccine, 5; pneumococcal and influenza vaccines, 7; and influenza vaccine, 1. Most patients (12 of 13) were receiving combination reverse transcriptase inhibitor antiretroviral therapy without protease inhibitors at the time of immunization. Baseline plasma HIV RNA was determined 1 month prior (11 of 13), 2 weeks prior (12 of 13) and on the day of immunization (12 of 13). Plasma HIV RNA was assayed at 2 weeks (11 of 13), 4 weeks (12 of 13) and 3 months (5 of 13) after immunization. T cell activation markers (HLA-DR+, CD38+ and CD45RO+, CD28+) were examined for both CD4+ and CD8+ lymphocytes on the day of immunization and 2 weeks after immunization for 11 children.

RESULTS

Only one child developed a >0.5-log increase in viral load at any time after immunization. There was no correlation between an increase in viral load and antibody response to pneumococcal vaccine. At least one activation marker increased (> 10%) for two children receiving pneumococcal vaccine and two children receiving pneumococcal and influenza vaccines. One of these children experienced an increase in viral load.

CONCLUSION

Immunization with pneumococcal and influenza vaccines, alone or in combination, is rarely associated with a significant increase in HIV plasma RNA in children receiving combination antiretroviral therapy.

Thymidine kinase gene therapy with concomitant topotecan chemotherapy for recurrent ovarian cancer

INTRODUCTION

Patients with recurrent ovarian cancer were treated with a replication-deficient recombinant adenovirus containing the herpes simplex virus thymidine kinase gene administered intraperitoneally (i.p.) followed by administration of an anti-herpetic prodrug and topotecan.

MATERIALS AND METHODS

A total of 10 patients with stage IIIc epithelial ovarian cancer underwent secondary debulking to < or =0.5 cm residual tumor. Patients with normal i.p. flow received i.p. delivery of adenovirus. Two patients each were treated on dose level 1 (2 x 10(10) vector particles (VP)), dose level 2 (2 x 10(11) VP), and dose level 3 (2 x 10(12) VP); four patients were treated on dose level 4 (2 x 10(13) VP). Acyclovir and topotecan were started 24 hours after vector delivery.

RESULTS

No patient treated at any dose level incurred unanticipated toxic effects, and all side effects resolved. The most common adverse event was myelosuppression: grade 3 or 4 thrombocytopenia with grade 2-4 anemia in three patients and grade 3 or 4 neutropenia in eight patients. Three patients developed thrombocytosis and three patients had a mild elevation of serum glutamic pyruvic transaminase/alanine aminotransferase. Temperature elevations that were not associated with detectable infection occurred in two patients.

DISCUSSION

I.p. delivery of adenoviral vector with concomitant topotecan chemotherapy was well tolerated without significant lasting toxicities. Side effects were independent of the dose of adenoviral vector.

A search for susceptibility loci for anorexia nervosa: methods and sample description

BACKGROUND

Eating disorders have not traditionally been viewed as heritable illnesses; however, recent family and twin studies lend credence to the potential role of genetic transmission. The Price Foundation funded an international, multisite study to identify genetic factors contributing to the pathogenesis of anorexia nervosa (AN) by recruiting affective relative pairs. This article is an overview of study methods and the clinical characteristics of the sample.

METHODS

All probands met modified DSM-IV criteria for AN; all affected first, second, and third degree relatives met DSM-IV criteria for AN, bulimia nervosa (BN), or eating disorder not otherwise specified (NOS). Probands and affected relatives were assessed diagnostically with the Structured Interview for Anorexia and Bulimia. DNA was collected from probands, affected relatives and a subset of their biological parents.

RESULTS

Assessments were obtained from 196 probands and 237 affected relatives, over 98% of whom are of Caucasian ancestry. Overall, there were 229 relative pairs who were informative for linkage analysis. Of the proband-relative pairs, 63% were AN-AN, 20% were AN-BN, and 16% were AN-NOS. For family-based association analyses, DNA has been collected from both biological parents of 159 eating-disordered subjects. Few significant differences in demographic characteristics were found between proband and relative groups.

CONCLUSIONS

The present study represents the first large-scale molecular genetic investigation of AN. Our successful recruitment of over 500 subjects, consisting of affected probands, affected relatives, and their biological parents, will provide the basis to investigate genetic transmission of eating disorders via a genome scan and assessment of candidate genes.

The diagnostic value of power Doppler measurements in the endometrium of women with postmenopausal bleeding

OBJECTIVE

The objective was to evaluate the accuracy of blood flow measurements by power Doppler in endometrial vessels in women with postmenopausal bleeding (PMB).

METHODS

Sixty consecutive patients with PMB participated in the study. Endometrial thickness and power Doppler measurements of small vessels in the endometrium and subendometrial tissue were performed prior to dilatation and curettage. Correlation between Doppler indices, endometrial thickness (by transvaginal sonography), and histopathologic examination was performed. A Student t test was used for statistical analysis with P < 0.05 as the level of significance.

RESULTS

Fourteen positive cases were found: 11 endometrial cancers, 1 sarcoma, 1 simple hyperplasia, and 1 complex hyperplasia with atypia. Measurements of endometrial thickness using a cutoff point of 5 mm revealed a sensitivity of 78% and specificity of 45.6% (P > 0.05, NS) for detecting endometrial pathology. Power Doppler measurements (pulsatility index cutoff point = 1.0) revealed a sensitivity of 85. 7% and specificity of 89% (P = 0.001) for detecting endometrial pathology.

CONCLUSIONS

The noninvasive methods for endometrial evaluation are not sensitive enough to exclude endometrial pathology. When invasive methods could not be performed, the combination of transvaginal sonography and power Doppler imaging provided the best results. When both modalities are negative, the probability of cancer is less than 5%.

Venlafaxine in children, adolescents, and young adults with autism spectrum disorders: an open retrospective clinical report

Autism is characterized by social deficits, communication and language impairments, narrow restricted interests, repetitive behaviors, inattention, and hyperactivity. While selective serotonin reuptake inhibitors have demonstrated efficacy in treating core symptoms of autism, norepinephrine reuptake inhibitors have demonstrated efficacy in symptoms of attention-deficit hyperactivity disorder (ADHD). An open, retrospective clinical study with venlafaxine evaluated its effect on core symptoms of autism as well as associated features of ADHD. Ten consecutive subjects meeting Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), criteria for an autism spectrum disorder were treated with venlafaxine, initiated at 12.5 mg per day and adjusted on a flexible basis. Six of 10 completers were judged to be sustained treatment responders, by scoring 1 (very much improved) or 2 (much improved) on the Clinical Global Impressions improvement scale. Venlafaxine was effective in low dosages (mean, 24.37 mg/day; range, 6.25 to 50 mg/day) and was well tolerated. Improvement was noted in repetitive behaviors and restricted interests, social deficits, communication and language function, inattention, and hyperactivity. Controlled treatment trials with venlafaxine are warranted in autism spectrum disorders.

EEG analysis with nonlinear deterministic and stochastic methods: a combined strategy

We describe nonlinear deterministic versus stochastic methodology, their applications to EEG research and the neurophysiological background underlying both approaches. Nonlinear methods are based on the concept of attractors in phase space. This concept on the one hand incorporates the idea of an autonomous (stationary) system, on the other hand implicates the investigation of a long time evolution. It is an unresolved problem in nonlinear EEG research that nonlinear methods per se give no feedback about the stationarity aspect. Hence, we introduce a combined strategy utilizing both stochastic and nonlinear deterministic methods. We propose, in a first step to segment the EEG time series into piecewise quasi-stationary epochs by means of nonparametric change point analysis. Subsequently, nonlinear measures can be estimated with higher confidence for the segmented epochs fulfilling the stationarity condition.

Eight centuries of north atlantic ocean atmosphere variability

Climate in the tropical North Atlantic is controlled largely by variations in the strength of the trade winds, the position of the Intertropical Convergence Zone, and sea surface temperatures. A high-resolution study of Caribbean sediments provides a subdecadally resolved record of tropical upwelling and trade wind variability spanning the past 825 years. These results confirm the importance of a decadal (12- to 13-year) mode of Atlantic variability believed to be driven by coupled tropical ocean-atmosphere dynamics. Although a well-defined interdecadal mode of variability does not appear to be characteristic of the tropical Atlantic, there is evidence that century-scale variability is substantial. The tropical Atlantic may also have been involved in a major shift in Northern Hemisphere climate variability that took place about 700 years ago.