Naturally absorbed lithium may prevent suicide attempts and deliberate self-harm while eicosapentaenoic acid may prevent deliberate self-harm and arachidonic acid may be a risk factor for deliberate self-harm: The updated different findings in new analyses

BACKGROUND

Since our previous investigation on the effects of trace lithium, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA) on deliberate self-harm and suicide attempts in 2018, to our knowledge, no replication study has been conducted on this topic.

SUBJECTS AND METHODS

We increased 37 new patients and totally 234 patients were re-analyzed to further investigate the association of suicide-related behaviors with levels of trace lithium, EPA, DHA, and AA in a different way to avoid multicollinearity.

RESULTS

Higher lithium levels were significantly associated with fewer suicide attempts and deliberate self-harm, higher EPA levels were significantly associated with fewer deliberate self-harm, and higher AA levels were significantly associated with more deliberate self-harm.

DISCUSSION

Although the sample size was only slightly larger than the previous study, the present results were clearly different from the previous ones due to the use of different statistical analyses to avoid multicollinearity.

CONCLUSION

The present findings suggest that naturally absorbed lithium may protect against suicide and deliberate self-harm, while naturally absorbed EPA may protect against deliberate self-harm. However, naturally absorbed AA may be a risk factor for deliberate self-harm.

Lithium in drinking water and suicide prevention: The largest nationwide epidemiological study from Japan

OBJECTIVES

The aims of the present study thus were (a) to further investigate the association between lithium levels in drinking water and suicide rates by adjusting relevant factors using the so far largest available dataset in Japan, (b) to confirm sex differences, (c) to estimate the effects of long-term exposure to trace lithium, (d) to investigate the effects of drinking bottled instead of tap water, and (e) to exploratorily investigate which lithium levels may be associated with lower suicide rates.

METHODS

Mean lithium levels in drinking water of all 808 cities and wards (ie, 785 cities of 46 prefectures and 23 wards of Tokyo) in Japan were examined in relation to mean suicide standardized mortality ratios (SMRs) during the 7 years from 2010 to 2016. Multiple regression analyses adjusted for the size of each population were used to investigate the association of lithium levels with suicide SMRs with adjustments for relevant factors.

RESULTS

The adjusted model showed significant inverse associations of lithium levels with total and male SMRs, but not with female SMRs. Neither the proportion of residents who continued to live in the same city nor the consumption of bottled water changed the association between lithium levels and suicide SMRs. Finally, it was 30 μg/L or more that was associated with lower suicide SMRs.

CONCLUSIONS

The present findings reconfirm the inverse association between lithium levels in drinking water and suicide rates particularly in the male population.

Naturally absorbed polyunsaturated fatty acids, lithium, and suicide-related behaviors: A case-controlled study

OBJECTIVE

Previous studies have investigated the effects of omega-3, omega-6 and lithium on suicide-related behaviors separately. This study was performed to comprehensively investigate the effects of naturally absorbed EPA, DHA, arachidonic acid and lithium in relation to suicide attempt and deliberate self-harm, with adjustment for each other.

METHODS

We analyzed plasma EPA, DHA, arachidonic acid levels and serum lithium levels of 197 patients including 33 patients with suicide attempts, 18 patients with deliberate self-harm, and 146 control patients.

RESULTS

Multivariate logistic regression analysis with adjustment for age, gender, EPA, DHA, arachidonic acid and log-transformed lithium levels revealed that the negative associations with EPA levels (adjusted OR 0.972, 95% CI 0.947-0.997, p = 0.031) and log-transformed lithium levels (adjusted OR 0.156, 95% CI 0.038-0.644, p = 0.01) and the positive association with DHA levels (adjusted OR 1.026, 95% CI 1.010-1.043, p = 0.002) were significant in patients with suicide attempts than in control patients. The analysis also demonstrated that the positive association with arachidonic acid levels (adjusted OR 1.015, 95% CI 1.005-1.025, p = 0.004) was significant in patients with deliberate self-harm than in control patients.

LIMITATIONS

The limitations are relatively small number of patients and the effects of demographics of individual patients could not be adjusted for the analyses.

CONCLUSIONS

The present findings suggest that, as naturally absorbed nutrients, higher EPA and lithium levels may be associated with less suicide attempt, and that higher arachidonic acid levels may be associated with more deliberate self-harm.

Reduced white matter integrity in borderline personality disorder: A diffusion tensor imaging study

BACKGROUND

Borderline personality disorder (BPD) has a pervasive pattern of instability in interpersonal relationships, self-image, and emotions. BPD may be linked to an abnormal brain anatomy, but little is known about possible impairments of the white matter microstructure in BPD or their relationship with impulsivity or risky behaviors. The aims of the present study were to explore the relationship between BPD and diffusion tensor imaging (DTI) parameters and psychological tests.

METHODS

We evaluated 35 un-medicated BPD patients in a medication-free state and 50 healthy controls (HCs). We performed DTI tractography in BPD patients and HCs. The Childhood Trauma Questionnaire (CTQ), Profile of Mood State (POMS), State-Trait Anxiety Inventory (STAI), Beck Depression Inventory (BDI), Social Adaptation Self-Evaluation Scale (SASS), and Depression and Anxiety Cognition Scale (DACS) were administered to BPD patients and HCs.

RESULTS

A tract-based spatial statistics (TBSS) revealed that the BPD group had three clusters with a significantly lower axial diffusivity (AD) than the HC group: one located mainly in the cingulum and the other mainly in the inferior front-occipital fasciculus and inferior longitudinal fasciculus. Regarding the AD values, one cluster correlated negatively and significantly with POMS (Depression) and it was located in the cingulum, while another cluster correlated positively and significantly with DACS (Future Denial) and it was located in the inferior front-occipital fasciculus (IFOF).

LIMITATIONS

The small sample size of this study prevents us from forming any definitive conclusions, meaning that more studies are needed to confirm our findings. We are unable to generalize our findings to include other ethnic groups.

CONCLUSIONS

Our results suggested that hypo-metabolism in a front-limbic network dysfunction is characterized by the cingulum and a front-occipital network dysfunction characterized by the occipital lobe, while an occipital-temporal network dysfunction characterized by the inferior longitudinal fasciculus.

Serum lithium levels and suicide attempts: a case-controlled comparison in lithium therapy-naive individuals

BACKGROUND

Several epidemiological studies have shown the inverse association of lithium levels in drinking water and suicide rates; however, it is necessary to perform a clinical study dealing with individual patients.

METHODS

We analyzed 199 patients including 31 patients with suicide attempts, 21 patients with self-harm, and 147 control patients. All were transferred to a university emergency department suffering from intoxication or injury, were aged 20 or more years, and were alive at the start of the study. The exclusion criteria consisted of suffering from schizophrenia and a past or present history of lithium therapy. These exclusions were applied because it is difficult to determine whether their suicide attempt was induced by the intent to end their life or by psychotic symptoms such as auditory hallucinations, and if the patient had received lithium therapy, the association between the small amount of lithium taken from drinking water and food and serum lithium levels cannot be detected.

RESULTS

There was a significant difference (p = 0.043) between the three groups whereby patients with suicide attempts had significantly lower lithium levels than control patients (p = 0.012) in males but not females. Multivariate logistic regression analysis with adjustment for age and gender revealed that patients with suicide attempts had significantly lower lithium levels than control patients (p = 0.032, odds ratio 0.228, 95% CI 0.059-0.883).

LIMITATIONS

The limitations of the present study are the nature of observational research which cannot reveal a causal relationship and the relatively small number of subjects.

CONCLUSIONS

The present findings suggest that higher serum lithium levels may be protective against suicide attempts in lithium therapy-naive individuals.

Gender differences in automatic thoughts and cortisol and alpha-amylase responses to acute psychosocial stress in patients with obsessive-compulsive personality disorder

INTRODUCTION

Obsessive-compulsive personality disorder (OCPD) has a pervasive pattern of preoccupation with orderliness, perfection, and mental and interpersonal control at the expense of flexibility, openness, and efficiency. The aims of the present study were to explore the relationship between OCPD and psychological stress and psychological tests.

METHODS

We evaluated 63 OCPD patients and 107 healthy controls (HCs). We collected saliva samples from patients and controls before and after a social stress procedure, the Trier Social Stress Test (TSST), to measure the concentrations of salivary alpha-amylase (sAA) and salivary cortisol. The Childhood Trauma Questionnaire (CTQ), Profile of Mood State (POMS), State-Trait Anxiety Inventory (STAI), Beck Depression Inventory (BDI), Social Adaptation Self-Evaluation Scale (SASS), and Depression and Anxiety Cognition Scale (DACS) were administered to patients and HCs.

RESULTS

Following TSST exposure, the salivary amylase and cortisol levels were significantly decreased in male patients compared with controls. Additionally, OCPD patients had higher CTQ, POMS, STAI, and BDI scores than HCs and exhibited significantly higher anxiety and depressive states. OCPD patients scored higher on future denial and threat prediction as per the DACS tool. According to a stepwise regression analysis, STAI, POMS, and salivary cortisol responses were independent predictors of OCPD.

CONCLUSIONS

Our results suggested that attenuated sympathetic and parasympathetic reactivity in male OCPD patients occurs along with attenuated salivary amylase and cortisol responses to the TSST. In addition, there was a significant difference between OCPD patients and HCs in child trauma, mood, anxiety, and cognition. The finding support the modeling role of cortisol (20min) on the relationships between STAI trait and depression among OCPD.

Different functioning of prefrontal cortex predicts treatment response after a selective serotonin reuptake inhibitor treatment in patients with major depression

BACKGROUND

Major depressive disorder (MDD) is often resistant to treatment with usual approaches. Patients with MDD have shown hypofunction of the frontotemporal cortex in verbal fluency test (VFT)-related near-infrared spectroscopy (NIRS).

METHODS

We examined whether the reactions to drug treatment in treatment-naive patients with MDD could be predicted by NIRS outcomes at the initial investigation. All subjects underwent psychological testing to determine levels of anxiety and depression. VFT was used to examine the functioning of the frontotemporal lobes. We administered selective serotonin reuptake inhibitors (SSRIs) for 12 weeks. Subjects included 28 patients with MDD with response to SSRIs (Response group), 19 with no response (Non-Response group), and 63 age-, sex-, and education years-matched healthy controls (HC).

RESULTS

We found in the frontotemporal region that hemodynamic responses were significantly smaller in patients with Response and Non-Response groups than in HC before treatment. We also found in the medial frontal region that hemodynamic responses were significantly larger in patients with Response groups than in patients with Non-Response group before treatment. Patients with MDD scored significantly higher anxiety and depressive states than those in HC on several measures. The Response and Non-Response groups also had higher scores in future denial, threat prediction, self-denial, past denial, and interpersonal threat sections of Anxiety Cognition Scale (DACS). According to the stepwise regression analysis, one variable was determined as independent predictors of response: confusion (Post-POMS).

LIMITATIONS

The number of patients and healthy controls was relatively small, and we will increase the number of participants in future studies. NIRS has reduced spatial resolution, which confuses the identification of the measurement position when using NIRS alone.

CONCLUSION

Cognitive vulnerabilities are associated with predictors of SSRI treatment response. Different hemodynamic activities in the frontotemporal cortex predict response to SSRI treatment in MDD.

Natural reduced water suppressed anxiety and protected the heightened oxidative stress in rats

BACKGROUND

In Japan, the effects of reduced water, such as hydrogen-rich electrolyzed reduced water and natural reduced water, like Hita Tenryosui water^®, have been examined. The purpose of the present study was to identify the role of natural reduced water in anxiety and blood biochemical analysis.

MATERIALS AND METHODS

Natural reduced water and distilled water were administered to rats for 180 consecutive days, and their effect on anxiety-like behavior and depression was examined by using elevated plus maze, light/dark, forced swimming, and conditioned fear tests. Before and after administration of natural reduced or distilled water, we performed blood and urine analyses.

RESULTS

Natural reduced water exhibited anxiolytic-like effects in the conditioned fear and elevated plus maze tests. The mean levels of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the natural reduced water were significantly lower than the distilled water group. Natural reduced water group also showed decrease in blood-urea nitrogen levels compared with the distilled water group.

CONCLUSION

These results indicate that natural reduced water may decrease anxiety-related behaviors and prevent heightened oxidative stress.

Hyperfunction of left lateral prefrontal cortex and automatic thoughts in social anxiety disorder: A near-infrared spectroscopy study

BACKGROUND

Patients with social anxiety disorder (SAD) experience unusual fear in normal social situations. The verbal fluency task (VFT) was administered while subjects were undergoing near-infrared spectroscopy (NIRS) scanning. The purpose of VFT was to examine the functions of the frontal and temporal lobes.

METHODS

Subjects included 145 drug-naïve patients with SAD and 152 healthy controls (HCs). All subjects underwent psychological testing to determine levels of anxiety and depression and to evaluate cognition.

RESULTS

The scores of patients with SAD indicated significantly higher anxiety and depressive states than those in HCs on several measures: Leibowitz Social Anxiety Scale (LSAS), Profile of Mood States (POMS), Spielberger Anxiety Inventory (STAI), Beck Depression Inventory (BDI), and Social Adaptation Self-evaluation Scale (SASS). The patients with SAD also had higher scores on the future denial, threat prediction, self-denial, past denial, and interpersonal threat sections of the Depression and Anxiety Cognition Scale (DACS). NIRS scanning revealed hyperactivity in the left frontal cortex of patients with SAD. Threat prediction scores on DACS were negatively correlated with oxy-Hb responses in the right frontal cortex.

LIMITATIONS

Further studies with a larger sample size are required to verify our findings.

CONCLUSIONS

The results of this study demonstrate the different mechanisms of the right and left frontal cortex in situations of social anxiety disorder.

Sex determines cortisol and alpha-amylase responses to acute physical and psychosocial stress in patients with avoidant personality disorder

INTRODUCTIONS

Avoidant personality disorder (AVPD) has excessive and pervasive anxiety and discomfort in social situations. The aims of this study were to explore the relationship between AVPD and physical and psychological stress and psychological tests.

METHODS

We evaluated 93 AVPD patients and 355 nonpatient controls by salivary amylase and cortisol responses during exposure to the Trier Social Stress Test (TSST) and electrical stimulation stress. Spielberger state-trait anxiety inventory (STAI), Profile of Mood State (POMS), Beck Depression Inventory (BDI), Depression and Anxiety Cognition Scale (DACS), and Childhood Trauma Questionnaire (CTQ) were administered.

RESULTS

Following electrical stimulation, salivary cortisol levels in female AVPD decreased significantly less than that in female's controls, but salivary cortisol levels did not show a difference between male AVPD patients and controls. Salivary alpha-amylase (sAA) levels did not show a difference between females or male AVPD patients and controls. Following TSST exposure, sAA levels did not show a difference between females or male AVPD patients and controls. Salivary cortisol levels did not show a difference between females or male AVPD patients and controls. In the AVPD patients, POMS scores were significantly higher compared with the controls. STAI, BDI, DACS scores, and CTQ significantly increased in the AVPD patients compared with the controls. LF in heart rate variability in AVPD significantly increased more compared with controls.

CONCLUSIONS

These results suggest that heightened sympathetic reactivity in female AVPD co-occurs with attenuated salivary cortisol responses to electric stimulation stress and there is a significant difference between AVPD and controls in mood, anxiety, social cognition, and automatic nerve systems.

Anxious temperament as a risk factor of suicide attempt

OBJECTIVE

Suicide has been reported to be associated with cyclothymic, irritable, depressive and anxious temperaments. In contrast, hyperthymic temperament has been reported to be protective against suicide. In the present study, we hypothesized that Japanese patients with suicide attempt may have higher scores of cyclothymic, irritable, depressive, and anxious temperaments but lower scores of hyperthymic temperament than non-suicidal patients. In order to examine this hypothesis, we investigated Japanese patients of a university emergency center.

METHODS

The association of temperament and suicide attempt was investigated in 116 patients referred to a university emergency center for intoxication or injury. Of them, 35 patients of suspected suicide attempt were categorized as 18 patients who intended to die with attempted suicide and suffered from self-inflicted but not fatal injury (Suicide Attempt II), 4 patients whose intention to die were undetermined although they suffered from self-inflicted injury (Undetermined Suicide-Related Behavior II), and 13 patients who had no intention to die although they suffered from self-inflicted injury (Self-Harm II). Logistic regression analyses and multiple regression analyses were used to identify factors associated with the present suicide attempt and the number of suicide attempts, respectively.

RESULTS

Anxious temperament scores were significantly and directly associated with Suicide Attempt II group whereas irritable temperament scores were associated with Self-Harm II group.

CONCLUSION

The present findings suggest that those with anxious temperament may have more suicide attempts than those with other temperaments, indicating anxious temperament as a risk factor of suicide attempt.

FKBP5 is associated with amygdala volume in the human brain and mood state: A voxel-based morphometry (VBM) study

The present study was to investigate the effects of 6 FK506 binding protein 51 (FKBP5) single nucleotide polymorphisms (SNPs) on brain structure using voxel-based morphometry (VBM) and the psychological tests to psychological stress. We genotyped 112 healthy controls with respect to 6 SNPs (rs) of FKBP5. We examined the Beck Depression Inventory and the State (STAI-S) and Trait (STAI-T) versions of the Spielberger Anxiety Inventory and the Profile of Mood States (POMS) to evaluate mood. The right amygdala was larger in subjects with the minor allele (C) of rs3800373 and rs992105 and the minor allele (T) of rs1360780. The right middle orbitofrontal region in those with the minor allele (C) of rs3800373 and the right inferior orbitofrontal region in those with the minor allele (T) of rs9470080 was larger. Both the amygdala volumes were associated significantly with FKBP5 SNPs. We found significant relationships between factors in POMS and the right and left amygdala and left insula. Our results suggest that FKBP5 SNPs are associated with the alternations of volumes in right amygdala and the right middle and inferior orbitofrontal region. Genetic variants of FKBP5 may be associated with depressive and anxiety state via differential effects on amygdala and orbitofrontal region.

Trace lithium is inversely associated with male suicide after adjustment of climatic factors

BACKGROUND

Previously, we showed the inverse association between lithium in drinking water and male suicide in Kyushu Island. The narrow variation in meteorological factors of Kyushu Island and a considerable amount of evidence regarding the role of the factors on suicide provoked the necessities of adjusting the association by the wide variation in sunshine, temperature, rain fall, and snow fall.

METHODS

To keep the wide variation in meteorological factors, we combined the data of Kyushu (the southernmost city is Itoman, 26°) and Hokkaido (the northernmost city is Wakkanai, 45°). Multiple regression analyses were used to predict suicide SMRs (total, male and female) by lithium levels in drinking water and meteorological factors.

RESULTS

After adjustment of meteorological factors, lithium levels were significantly and inversely associated with male suicide SMRs, but not with total or female suicide SMRs, across the 153 cities of Hokkaido and Kyushu Islands. Moreover, annual total sunshine and annual mean temperature were significantly and inversely associated with male suicide SMRs whereas annual total rainfall was significantly and directly associated with male suicide SMRs.

LIMITATIONS

The limitations of the present study include the lack of data relevant to lithium levels in food and the proportion of the population who drank tap water and their consumption habits.

CONCLUSIONS

The present findings suggest that trace lithium is inversely associated with male but not female suicide after adjustment of meteorological factors.

Genetic association of the transcription of neuroplasticity-related genes and variation in stress-coping style

INTRODUCTION

Stress coping has been defined as the cognitive and behavioral efforts made to conquer, endure, or decrease external and internal demands and the conflicts between them. It has two main elements: the control or modification of the person-environment relationship causing the stress (i.e., problem-focused coping) and/or regulation of stressful feelings (i.e., emotion-focused coping). Research suggests that the expressions of brain-derived neurotrophic factor (BDNF) and neurotrophic tyrosine kinase receptor type 2 (NTRK2) play important roles in brain adaptation to investigate stress. To clarify the genetic basis of stress coping, we investigated the association of stress-coping strategies and social adaptation with single-nucleotide polymorphisms (SNPs) involved in neural plasticity, anxiety, and depression.

METHODS

In 252 healthy controls (94 women; 158 men), we measured and estimated the stress-coping style using the Lazarus-type stress-coping inventory, ego aptitude scale (EAS), and social adaptation self-evaluation scale (SASS). We investigated one SNP of BDNF (rs6265, Val/Met) and five SNPs of NTRK2 (rs11140800, rs1187286, rs1867283, rs1147198, and rs10868235).

RESULTS

We observed significant associations between BDNF and emotion-focused strategies, seeking social support, self-control, and distancing. We also found significant associations between NTRK2 and cognitive strategies, problem-solving, confrontive- coping, seeking social support, distancing and positive reappraisal. Significant associations were also found between BDNF and critical attitudes and between NTRK2 and all seven ego-related factors on the EAS. In the SASS, the minor allele rs1867283 of NTRK2 had a significantly higher score than the heterozygote.

CONCLUSIONS

These findings may provide insights into the partial effects of genetic mutations in BDNF and NTRK2 on stress tolerance and personality.

Gender determines cortisol and alpha-amylase responses to acute physical and psychosocial stress in patients with borderline personality disorder

Borderline personality disorder (BPD) is characterized by affective instability, unstable relationships, and identity disturbance. We measured salivary alpha-amylase (sAA) and salivary cortisol levels in all participants during exposure to the Trier Social Stress Test (TSST) and an electric stimulation stress. Seventy-two BPD patients were compared with 377 age- and gender- matched controls. The State and Trait versions of the Spielberger Anxiety Inventory test (STAI-S and STAI-T, respectively), the Profile of Mood State (POMS) tests, and the Beck Depression Inventory (BDI), the Depression and Anxiety Cognition Scale (DACS) were administered to participants before electrical stimulation. Following TSST exposure, salivary cortisol levels significantly decreased in female patients and significantly increased in male patients compared with controls. POMS tension-anxiety, depression-dejection, anger-hostility, fatigue, and confusion scores were significantly increased in BPD patients compared with controls. In contrast, vigor scores were significantly decreased in BPD patients relative to controls. Furthermore, STAI-T and STAI-S anxiety scores and BDI scores were significantly increased in BPD patient compared with controls. DACS scores were significantly increased in BPD patient compared with controls. Different stressors (e.g., psychological or physical) induced different responses in the HPA and SAM systems in female or male BPD patients.

Association of microcephalin 1, syntrophin-beta 1, and other genes with automatic thoughts in the Japanese population

Automatic thoughts may be risk factors for depression and anxiety, and should be detected early. However, the genetic basis of automatic thoughts remains unclear. This study aims to investigate the genetic association of automatic thoughts with SNPs (single nucleotide polymorphisms) involved in cognition, neurogenesis, neuronal cell structure, neurotransmitters, hypothalamus-pituitary adrenal axis and psychiatric illness. The study included 610 healthy participants. We used the Depression and Anxiety Cognition Scale (DACS), a Japanese psychological questionnaire, to assess automatic thoughts. Twenty-five SNPs including COMT, BDNF, FKBP5, SNTB1 (syntrophin-beta 1, rs4512418), and MCPH1 (microcephalin 1, rs2911968) were selected according to their minor allele frequency. Linear regression models were used to test association of mean DACS scores with each allele (major-allele homozygote, heterozygote, and minor-allele homozygote). The significant α-value was set at α < 0.002. Statistical analysis was conducted using SNPStats. Call rates for all genotypes were >98%. Eighteen SNPs did not deviate from Hardy-Weinberg equilibrium, and 7 were excluded from statistical analysis. Significant associations of SNTB1 with interpersonal threat and MCPH1 with future denial were observed only in females. SNTB1 and MCPH1 are located on chromosome 8, which may be involved in neuroticism, avoidant personality and depression. Our results demonstrated that DACS scores showing significant interaction with the 2 SNPs may be regarded as appropriate traits to detect the diathesis of automatic thoughts. The 2 SNPs may be important loci in research on cognitive vulnerability to depression and anxiety.

Association of BDNF Val66Met polymorphism with HPA and SAM axis reactivity to psychological and physical stress

BACKGROUND

Decreased expression of brain-derived neurotrophic factor (BDNF) is implicated in enhanced stress responses. The BDNF Val66Met polymorphism is associated with psychological changes; for example, carriers of the Met allele exhibit increased harm avoidance as well as a higher prevalence of depression and anxiety disorder.

METHODS

To analyze the effects of BDNF Val66Met on stress responses, we tested 226 university students (88 women and 138 men) using a social stress procedure (Trier Social Stress Test [TSST]) and an electrical stimulation stress test. Stress indices were derived from repeated measurements of salivary α-amylase, salivary cortisol, heart rate, and psychological testing during the stress tests. All subjects were genotyped for the Val66Met polymorphism (G196A).

RESULTS

A significant three-way interaction (time [3 levels] × BDNF [Val/Val, Val/Met, Met/Met]; P<0.05) was demonstrated that revealed different salivary cortisol responses in the TSST but not in electrical stimulation. Met/Met women had stronger cortisol responses than Val/Met and Val/Val individuals in the TSST. Met/Met men exhibited stronger salivary cortisol responses than Val/Met and Val/Val individuals in the TSST.

CONCLUSION

These results indicate that a common, functionally significant polymorphism in BDNF had different effects on hypothalamic-pituitary-adrenocortical axis reactivity but not on sympathetic adrenomedullary reactivity in TSST and electrical stimulation tests.

Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in obsessive-compulsive disorder patients

Salivary α-amylase (sAA) serves as a marker of sympathoadrenal medullary system (SAM) activity. Salivary AA has not been extensively studied in obsessive-compulsive disorder (OCD) patients. In the current study, 45 OCD patients and 75 healthy volunteers were assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Profile of Mood State (POMS), and the State-Trait Anxiety Inventory (STAI). Measures of heart rate variability (HRV), sAA, and salivary cortisol were also obtained following the application of electrical stimulation stress. The Y-BOCS and POMS Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue, and Confusion scores were significantly increased in patients with OCD compared with healthy controls. In contrast, Vigor scores were significantly decreased in patients with OCD relative to scores in healthy controls. There was no difference in HRV between the patients and the controls. Salivary AA levels in female and male OCD patients were significantly elevated relative to controls both before and after electrical stimulation. In contrast, there were no differences in salivary cortisol levels between OCD patients and controls. The elevated secretion of sAA before and after stimulation may suggest an increased responsiveness to novel and uncontrollable situations in patients with OCD. An increase in sAA might be a characteristic change of OCD.

Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in patients with the generalized type of social anxiety disorder

INTRODUCTION

Social anxiety disorder is believed to be a stress-induced disease. Although it can be inferred from the symptoms during attacks that there exists some abnormality of autonomic nervous system in any of the stress systems in social anxiety disorder, little evidence has been reported. This study focused on comparing the reactivity of 2 stress systems, the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis in patients with social anxiety disorder.

METHODS

32 patients with the generalized type of social anxiety disorder were compared with 80 age- and gender-matched controls. We collected saliva samples from patients and controls before and after electrical stimulation to measure the concentrations of salivary alpha-amylase (sAA) and salivary cortisol. Profile of Mood State (POMS) and State-Trait Anxiety Inventory (STAI) scores and Heart Rate Variability (HRV) were also determined following stimulation.

RESULTS

SAA in patients displayed a significantly higher level at baseline and a significantly larger response to electrical stimulation as compared to controls, whereas no group differences were seen in any HRV. Neither within-subject nor group differences were seen in salivary cortisol levels.

CONCLUSIONS

These results suggest that SAD patients displayed enhanced ANS (but not HPA axis) activity vs. healthy controls.

The value of ethyl cysteinate dimer single photon emission computed tomography in predicting antidepressant treatment response in patients with major depression

OBJECTIVE

The purpose of this study is to examine whether the reversal of compromised regional cerebral blood flow (rCBF) in older patients with major depressive disorder (MDD) is dependent on specific parameters of selective serotonin reuptake inhibitor (SSRI) treatment and to examine the efficacy of such treatment.

METHODS

Forty-five patients with moderate MDD were studied following 8 weeks of treatment with SSRIs. Twelve patients displayed a positive response to SSRIs, whereas 33 patients did not respond to SSRI treatment. A comparison group of 30 healthy volunteers was also studied. The age of all participants was greater than 50 years. Age, gender, and the Hamilton Rating Scale for Depression scores were examined. The rCBF was assessed using 99mTc-ethyl cysteinate dimer single photon emission computed tomography after SSRI treatment.

RESULTS

The rCBF levels in the right middle frontal cortex in non-responsive MDD patients were lower compared with responsive MDD patients. Compared with healthy controls, non-responders had significantly lower rCBF levels in the bilateral middle frontal cortex and insula and had significantly higher rCBF levels in the bilateral inferior frontal cortex and left middle temporal cortex. Compared with healthy controls, responders had significantly higher rCBF levels in the left inferior frontal, middle temporal, precentral, and fusiform gyrus. We found no changes in single photon emission computed tomography between pre-treatment and post-treatment stages for the responders to SSRI treatment.

CONCLUSION

Hypoperfusion in older, non-responsive MDD patients was primarily localized in the middle frontal cortex. It is possible that the responders to SSRI treatment at baseline already displayed higher rCBF values in the frontal regions.

Serum ghrelin levels and the effects of antidepressants in major depressive disorder and panic disorder

BACKGROUND

Two opposing models for the action of ghrelin in the behavioral responses to stress were recently proposed. Some studies suggest that an increase in ghrelin contributes to the mechanisms responsible for the development of stress-induced depression and anxiety, while others suggest that it helps minimize what otherwise would be more severe manifestations of depression and anxiety following stress.

METHODS

We measured serum ghrelin levels, Profile of Mood States (POMS) scores and State-Trait Anxiety Inventory scores in nonresponders (treatment-resistant patients; 30) and responders (38) with major depressive disorder (MDD), nonresponders (29) and responders (51) with panic disorder and 97 healthy controls.

RESULTS

The ghrelin concentration in nonresponders with MDD was higher than that of responders with MDD and normal controls. The ghrelin concentration in nonresponders with panic disorder was higher than that of normal controls. POMS vigor scores in patients with MDD and panic disorder were significantly decreased compared with those in healthy controls. Other POMS scores in patients with MDD and panic disorder were significantly increased compared with those of healthy controls. Trait and state anxiety of the State-Trait Anxiety Inventory in MDD and panic disorder patients were higher than those in healthy controls.

CONCLUSIONS

These results indicate that decreased serum ghrelin levels might be associated with antidepressant treatment to confer the maximum therapeutic effect in patients with MDD and panic disorder.

Salivary alpha-amylase and cortisol responsiveness following electrically stimulated physical stress in bipolar disorder patients

BACKGROUND

Bipolar disorder (BP) is often associated with a change in hypothalamus- pituitary-adrenal axis function change due to chronic stress. Salivary α-amylase (sAA) levels increase in response to psychosocial stress and thus function as a marker of sympathoadrenal medullary system activity. However, sAA has been studied less often than salivary cortisol in BP patients.

METHOD

We measured Profile of Mood States and State-Trait Anxiety Inventory scores, heart rate variability, and salivary cortisol levels during electrical stimulation stress in 25 BP patients and 22 healthy volunteers.

RESULTS

Tension-anxiety, depression-dejection, anger-hostility, fatigue, and confusion scores in BP patients significantly increased compared with those of the healthy controls. In contrast, the vigor scores of BP patients significantly decreased compared with those of the healthy controls. Significant difference in the sAA levels was observed between BP patients and healthy controls. sAA of female patients was significantly higher than that of female healthy controls, and sAA in male patients tended to be higher than that of male healthy controls. No difference in salivary cortisol was observed between BP patients and the healthy controls. Only three time points were measured before and after the electrical stimulation stress. Furthermore, sAA secretion by BP patients increased before and after electrical stimulation.

CONCLUSION

These preliminary results suggest that sAA may be a useful biological marker for BP patients.

The thyrotropin-releasing hormone test may predict recurrence of clinical depression within ten years after discharge

OBJECTIVES

The underlying pathogenic mechanisms and predictors of recurrence in major depressive disorder are still largely unknown. Hypothalamic-pituitary-thyroid (HPT) axis and hypothalamus-pituitary-adrenocortical (HPA) axis dysregulation are thought to be related to the development and course of depression.

DESIGN AND SETTING

Over a ten-year period, we investigated whether the results of thyrotropin-releasing hormone (TRH) testing and combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) testing could be correlated with the recurrence of depression in 25 outpatients with clinically remitted major depression for at least 10 years.

MATERIALS AND METHODS

Twenty-five patients (16 women and 9 men, 48.1 years of age, SD=11.4, range 22-84) with major depressive disorder were available for evaluation during hospitalization. TRH and DEX/CRH tests were administered at admission.

RESULTS

Patients who recurred within ten years after remission exhibited significantly higher thyroid stimulating hormone (TSH) responses to TRH at the time of admission compared to those who did not recur. There was no significant correlation between recurrence and DEX/CRH levels after controlling for age, sex, and body mass index.

CONCLUSION

The findings of this study suggest that the TRH test may predict future recurrence in patients with depression.

An uncommon case of random fire-setting behavior associated with Todd paralysis: a case report

BACKGROUND

The association between fire-setting behavior and psychiatric or medical disorders remains poorly understood. Although a link between fire-setting behavior and various organic brain disorders has been established, associations between fire setting and focal brain lesions have not yet been reported. Here, we describe the case of a 24-year-old first time arsonist who suffered Todd's paralysis prior to the onset of a bizarre and random fire-setting behavior.

CASE PRESENTATION

A case of a 24-year-old man with a sudden onset of a bizarre and random fire-setting behavior is reported. The man, who had been arrested on felony arson charges, complained of difficulties concentrating and of recent memory disturbances with leg weakness. A video-EEG recording demonstrated a close relationship between the focal motor impairment and a clear-cut epileptic ictal discharge involving the bilateral motor cortical areas. The SPECT result was statistically analyzed by comparing with standard SPECT images obtained from our institute (easy Z-score imaging system; eZIS). eZIS revealed hypoperfusion in cingulate cortex, basal ganglia and hyperperfusion in frontal cortex,. A neuropsychological test battery revealed lower than normal scores for executive function, attention, and memory, consistent with frontal lobe dysfunction.

CONCLUSION

The fire-setting behavior and Todd's paralysis, together with an unremarkable performance on tests measuring executive function fifteen months prior, suggested a causal relationship between this organic brain lesion and the fire-setting behavior. The case describes a rare and as yet unreported association between random, impulse-driven fire-setting behavior and damage to the brain and suggests a disconnection of frontal lobe structures as a possible pathogenic mechanism.

Hippocampal agenesis in an individual who engaged in violent criminal behaviors after discontinuing carbamazepine and paroxetine treatment

Antidepressant discontinuation syndrome (ADS) occurs after abrupt discontinuation of an antidepressant medication. A 23-year-old man with right hippocampal agenesis demonstrated sexual crime (hypersexuality) since the age of eight and had been successfully treated with carbamazepine since the age of 13. He had required increased doses of paroxetine and carbamazepine owing to the development of an unstable affect after quitting his job. He abruptly stopped taking his medication for 3 days and his criminal behaviors re-emerged. We examined changes in brain structure and activity before and after medication cessation, using MRI and functional MRI (fMRI). The image of a girl in a swimsuit increased activity in the thalamus only after medication discontinuation. The alteration in thalamic activity might induce hypersexuality. We conclude that a primary hypersexuality had been suppressed with carbamazepine and paroxetine treatment, and the discontinuation of the medication caused the hypersexuality.

Differences in salivary alpha-amylase and cortisol responsiveness following exposure to electrical stimulation versus the Trier Social Stress Tests

Background

Cortisol is an essential hormone in the regulation of the stress response along the HPA axis, and salivary cortisol has been used as a measure of free circulating cortisol levels. Recently, salivary alpha-amylase (sAA) has also emerged as a novel biomarker for psychosocial stress responsiveness within the sympathetic adrenomedullary (SAM) system.

Principal Findings

We measured sAA and salivary cortisol in healthy volunteers after exposure to the Trier Social Stress Test (TSST) and electric stimulation stress. One hundred forty-nine healthy volunteers participated in this study. All subjects were exposed to both the TSST and electric stimulation stress on separate days. We measured sAA and salivary cortisol levels three times immediately before, immediately after, and 20 min after the stress challenge. The State (STAI-S) and Trait (STAI-T) versions of the Spielberger Anxiety Inventory test and the Profile of Mood State (POMS) tests were administered to participants before the electrical stimulation and TSST protocols. We also measured HF, LF and LF/HF Heart Rate Variability ratio immediately after electrical stimulation and TSST exposure. Following TSST exposure or electrical stimulation, sAA levels displayed a rapid increase and recovery, returning to baseline levels 20 min after the stress challenge. Salivary cortisol responses showed a delayed increase, which remained significantly elevated from baseline levels 20 min after the stress challenge. Analyses revealed no differences between men and women with regard to their sAA response to the challenges (TSST or electric stimulations), while we found significantly higher salivary cortisol responses to the TSST in females. We also found that younger subjects tended to display higher sAA activity. Salivary cortisol levels were significantly correlated with the strength of the applied electrical stimulation.

Conclusions

These preliminary results suggest that the HPA axis (but not the SAM system) may show differential response patterns to distinct kinds of stressors.

Association of CRHR1 and CRHR2 with major depressive disorder and panic disorder in a Japanese population

Major depressive disorder (MDD) and panic disorder (PD) are common and disabling medical disorders with stress and genetic components. Dysregulation of the stress response of the hypothalamic-pituitary-adrenal axis, including the corticotrophin-releasing hormone (CRH) signaling via primary receptors (CRHR1 and CRHR2), is considered to play a major role for onset and recurrence in MDD and PD. To confirm the association of CRHR1 and CRHR2 with MDD and PD, we investigated 12 single nucleotide polymorphisms (SNPs) (rs4076452, rs7209436, rs110402, rs242924, rs242940, and rs173365 for CRHR1 and rs4722999, rs3779250, rs2267710, rs1076292, rs2284217, and rs226771 for CRHR2) in MDD patients (n = 173), PD patients (n = 180), and healthy controls (n = 285). The SNP rs110402 and rs242924 in the CRHR1 gene and the rs3779250 in the CRHR2 gene were associated with MDD. The SNP rs242924 in the CRHR1 gene was also associated with PD. The T-A-T-G-G haplotype consisting of rs7209436 and rs173365 in CRHR1 was positively associated with MDD. The T-A haplotype consisting of rs7209436 and rs110402 in CRHR1 was positively associated with MDD. The C-C haplotype consisting of rs4722999 and rs37790 in CRHR1 was associated with PD. These results provide support for an association of CRHR1 and CRHR2 with MDD and PD.

Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in major depressive disorder patients

Major depressive disorder (MDD) is often associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis by chronic stress. In comparison, psychosocial stress-induced activation of salivary α-amylase (sAA) functions as a marker of sympathoadrenal medullary system (SAM) activity. However, in contrast to salivary cortisol, sAA has been less extensively studied in MDD patients. The present study measured sAA and salivary cortisol levels in patients with MDD. The authors determined Profile of Mood State (POMS) and State-Trait anxiety Inventory (STAI) scores, Heart Rate Variability (HRV), and sAA and salivary cortisol levels in 88 patients with MDD and 41 healthy volunteers following the application of electrical stimulation stress. Patients with major depressive disorder were 8 points or more on Hamilton Depression Scale (HAM-D) scores. Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue, and Confusion scores in patients with major depressive disorder were significantly increased compared to healthy controls. In contrast, Vigor scores in patients with MDD were significantly decreased compared with healthy controls. There was no difference in heart rate variability measures between MDD patients and healthy controls. The threshold of electrical stimulation applied in MDD patients was lower than that in healthy controls. SAA levels in female MDD patients were significantly elevated relative to controls both before and after electrical stimulation. Finally, there were no differences in salivary cortisol levels between major depressive patients and controls. In the present study only three time points were explored. Furthermore, the increased secretion of sAA before and after stimulation could allude to an increased responsiveness of novel and uncontrollable situations in patients with MDD. These preliminary results suggest that sAA might be a useful biological marker of MDD.

Aripiprazole augmentation in 13 patients with refractory obsessive-compulsive disorder: a case series

OBJECTIVES

The primary treatment for obsessive-compulsive disorder (OCD) is selective serotonin reuptake inhibitors (SSRI). However, approximately a third of patients do not respond to SSRIs and remain chronically affected.

METHODS

Therefore, we added aripiprazole to SSRI therapy for 13 patients with treatment-refractory OCD (subjects who failed to respond to SSRI therapy for at least 2 months, and for an average of 508 days). Participants underwent at least 7 weeks of treatment with aripiprazole augmentation.

RESULTS

Patients were evaluated using the Y-BOCS and GAF scales. Aripiprazole (3-12 mg)/SSRI co-therapy significantly improved Y-BOCS and GAF scores. However, many patients needed to take antiparkinsonian drugs to control extrapyramidal symptoms.

CONCLUSIONS

These results suggest that aripiprazole augmentation of SSRI therapy may be effective for treatment-refractory OCD.

Administration of antisense DNA for GPR39-1b causes anxiolytic-like responses and appetite loss in rats

The G protein-coupled receptor 39-b (GPR39-1b) is a splice variant of which is expressed in the central nervous and gastrointestinal systems. Previously, GPR39-1b was proposed to be the receptor for obestatin, but current evidence does not support this hypothesis. The purpose of the present work was to identify the role of GPR39-1b in anxiety and eating behaviors. Antisense oligonucleotides were infused at a constant rate into the cerebral lateral ventricles of rats and their effect on anxiety-like behavior and food intake was monitored. GPR39-1b antisense oligonucleotides produced anxiolytic-like effects in the elevated-plus maze test and in the black and white box test. Antisense oligonucleotides also decreased food intake. These results indicate that inhibition of GPR39-1b induces a decrease in anxiety-related behaviors and disturbs appetite.

Elevated salivary α-amylase and cortisol levels in unremitted and remitted depressed patients

Abstract Objective. Major depressive disorder (MDD) is often associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis via chronic stress. Psychosocial stress-induced activation of salivary α-amylase (sAA) represents sympathoadrenal medullary system (SAM) activity, and sAA has become an emerging biomarker for sympathetic nervous system activity. In contrast to salivary cortisol, sAA has been less extensively studied in depressed patients. The present study sought to address this problem by measuring sAA and salivary cortisol levels in patients with major depressive disorder. Methods. The authors recorded Spielberger State-Trait Anxiety Inventory (STAI) scores along with, levels of sAA and salivary cortisol in 28 patients with unremitted major depressive disorder, 43 remitted patients and 103 healthy volunteers. Results. STAI (State or Trait) measurements in unremitted patients with MDD were significantly increased compared with healthy controls and remitted patients. SAA and cortisol levels in unremitted patients were also significantly elevated compared to controls and remitted patients. Finally, sAA levels were significantly correlated with HRSD in unremitted patients with MDD. Conclusion. These preliminary results suggest that sAA may be a state-dependent marker of major depressive disorder in addition to salivary cortisol.

Serum hepatocyte growth factor levels and the effects of antidepressants in panic disorder

Previous animal studies have suggested that hepatocyte growth factor (HGF) could be associated with depression- and anxiety-related behaviors. Our aim was to relate serum HGF levels with State-Trait Anxiety Inventory (STAI), Profile of Mood State (POMS), and Revised NEO Personality Inventory (NEO-PI-R) scores in patients with panic disorder (with or without agoraphobia) and healthy controls. We examined 67 patients with panic disorders and 97 controls. Patients were split into two groups according to whether they exhibited a 50% improvement in test scores (good/high response group: n = 26) or not (poor/low response group: n = 41). In both healthy control and panic disorder individuals, there were no significant associations between HGF serum levels and STAI or NEO-PI-R scores. However, there was a significant correlation between serum HGF levels and fatigue in healthy control subjects in as scored by POMS testing. HGF concentration in the good/high response group was significantly elevated compared to both the low/poor response group (p < 0.01) and the control group (p < 0.01). HGF levels in the poor response group did not differ from the control group (p = 0.48). These results indicate that increased serum HGF levels might be a requirement for antidepressant efficacy in patients with panic disorders.

Protein network inference from multiple genomic data: a supervised approach

MOTIVATION

An increasing number of observations support the hypothesis that most biological functions involve the interactions between many proteins, and that the complexity of living systems arises as a result of such interactions. In this context, the problem of inferring a global protein network for a given organism, using all available genomic data about the organism, is quickly becoming one of the main challenges in current computational biology.

RESULTS

This paper presents a new method to infer protein networks from multiple types of genomic data. Based on a variant of kernel canonical correlation analysis, its originality is in the formalization of the protein network inference problem as a supervised learning problem, and in the integration of heterogeneous genomic data within this framework. We present promising results on the prediction of the protein network for the yeast Saccharomyces cerevisiae from four types of widely available data: gene expressions, protein interactions measured by yeast two-hybrid systems, protein localizations in the cell and protein phylogenetic profiles. The method is shown to outperform other unsupervised protein network inference methods. We finally conduct a comprehensive prediction of the protein network for all proteins of the yeast, which enables us to propose protein candidates for missing enzymes in a biosynthesis pathway.

AVAILABILITY

Softwares are available upon request.

Administration of antisense DNA for ghrelin causes an antidepressant and anxiolytic response in rats

RATIONALE

Ghrelin is a peptide of 28 amino acids found in mammals that increases the release of growth hormone, food intake, and body weight.

OBJECTIVES

We investigated the relationship between ghrelin and the states of anxiety and depression by giving rats either antisense DNA for ghrelin, scrambled DNA or vehicle into the lateral ventricle of rats.

RESULTS

In forced swimming tests, rats that received antisense DNA decreased the length of time that they were immobile in the water. Ghrelin antisense oligonucleotides produced an anxiolytic-like effects in the elevated plus maze test, black and white test, or conditioned fear tests. Treatment with antisense DNA for ghrelin significantly decreased rat body weight. No significant effect on general locomotor activity was seen.

CONCLUSIONS

These results suggest that administration of antisense DNA for ghrelin causes an antidepressant and anxiolytic response in rats.

The role of log-normal dynamics in the evolution of biochemical pathways

The study of the scale-free topology in non-biological and biological networks and the dynamics that can explain this fascinating property of complex systems have captured the attention of the scientific community in the last years. Here, we analyze the biochemical pathways of three organisms (Methanococcus jannaschii, Escherichia coli, Saccharomyces cerevisiae) which are representatives of the main kingdoms Archaea, Bacteria and Eukaryotes during the course of the biological evolution. We can consider two complementary representations of the biochemical pathways: the enzymes network and the chemical compounds network. In this article, we propose a stochastic model that explains that the scale-free topology with exponent in the vicinity of gamma approximately 3/2 found across these three organisms is governed by the log-normal dynamics in the evolution of the enzymes network. Precisely, the fluctuations of the connectivity degree of enzymes in the biochemical pathways between evolutionary distant organisms follow the same conserved dynamical principle, which in the end is the origin of the stationary scale-free distribution observed among species, from Archaea to Eukaryotes. In particular, the log-normal dynamics guarantees the conservation of the scale-free distribution in evolving networks. Furthermore, the log-normal dynamics also gives a possible explanation for the restricted range of observed exponents gamma in the scale-free networks (i.e., gamma > or = 3/2). Finally, our model is also applied to the chemical compounds network of biochemical pathways and the Internet network.

Flexible construction of hierarchical scale-free networks with general exponent

Extensive studies have been done to understand the principles behind architectures of real networks. Recently, evidence for hierarchical organization in many real networks has also been reported. Here, we present a hierarchical model that reproduces the main experimental properties observed in real networks: scale-free of degree distribution P (k) [frequency of the nodes that are connected to k other nodes decays as a power law P (k) approximately k(-gamma) ] and power-law scaling of the clustering coefficient C (k) approximately k(-1) . The major points of our model can be summarized as follows. (a) The model generates networks with scale-free distribution for the degree of nodes with general exponent gamma>2 , and arbitrarily close to any specified value, being able to reproduce most of the observed hierarchical scale-free topologies. In contrast, previous models cannot obtain values of gamma>2.58 . (b) Our model has structural flexibility because (i) it can incorporate various types of basic building blocks (e.g., triangles, tetrahedrons, and, in general, fully connected clusters of n nodes) and (ii) it allows a large variety of configurations (i.e., the model can use more than n-1 copies of basic blocks of n nodes). The structural features of our proposed model might lead to a better understanding of architectures of biological and nonbiological networks.

Extraction of correlated gene clusters from multiple genomic data by generalized kernel canonical correlation analysis

MOTIVATION

A major issue in computational biology is the reconstruction of pathways from several genomic datasets, such as expression data, protein interaction data and phylogenetic profiles. As a first step toward this goal, it is important to investigate the amount of correlation which exists between these data.

RESULTS

These methods are successfully tested on their ability to recognize operons in the Escherichia coli genome, from the comparison of three datasets corresponding to functional relationships between genes in metabolic pathways, geometrical relationships along the chromosome, and co-expression relationships as observed by gene expression data.

[G-protein coupled peptide receptors and their ligands in human genome]

The G-protein coupled peptide receptors as well as their ligands, endogenous peptides, are involved in regulation of many important physiological processes in the organism and therefore represent attractive targets for pharmaceutical investigation and drug design. With the completion of the human draft genome sequencing, it has become possible to take a comprehensive picture of all genes encoding both peptide receptors and peptides themselves. In the present study a first attempt has been made to carry out a comprehensive analysis of G-protein coupled peptide receptors and their respective endogenous peptide ligands in the human genome. We searched the genome sequence by means of sequential application of standard bioinformatical methods (such as homology search, hierarchical cluster analysis, building of hmm-profiles etc.) with the goal of identifying all the components of peptide ligand/receptor system in the human genome. As a result of this search it was concluded that the probable number of functional peptide receptors in the human genome is 218, and the probable peptide precursors' number is 126 amino acid sequences. These two groups include, respectively, 12 novel G-protein coupled peptide receptors and 10 novel peptide precursors, discovered in the present study. The probable biological functions of newly discovered candidates were determined based on the sequence similarity to the earlier known proteins. Classification of all peptide GPCRs and their ligands based on the ligand specificity was performed for all probable G-protein coupled peptide receptors. The issue of ligand-receptor specificity in the human genome is also discussed.

Extraction of correlated gene clusters by multiple graph comparison

This paper presents a new method to extract a set of correlated genes with respect to multiple biological features. Relationships among genes on a specific feature are encoded as a graph structure whose nodes correspond to genes. For example, the genome is a graph representing positional correlations of genes on the chromosome, the pathway is a graph representing functional correlations of gene products, and the expression profile is a graph representing gene expression similarities. When a set of genes are localized in a single graph, such as a gene cluster on the chromosome, an enzyme cluster in the metabolic pathway, or a set of coexpressed genes in the microarray gene expression profile, this may suggest a functional link among those genes. The functional link would become stronger when the clusters are correlated; namely, when a set of corresponding genes form clusters in multiple graphs. The newly introduced heuristic algorithm extracts such correlated gene clusters as isomorphic subgraphs in multiple graphs by using inter-graph links that are defined based on biological relevance. Using the method, we found E.coli correlated gene clusters in which genes are related with respect to the positions in the genome and the metabolic pathway, as well as the 3D structural similarity. We also analyzed protein-protein interaction data by two-hybrid experiments and gene coexpression data by microarrays in S.cerevisiae, and estimated the possibility of utilizing our method for screening the datasets that are likely to contain many false positive relations.

Characterization of genes encoding multi-domain proteins in the genome of the filamentous nitrogen-fixing Cyanobacterium anabaena sp. strain PCC 7120

Computational analysis of gene structures in the genome of Anabaena sp. PCC 7120 revealed the presence of a large number of genes encoding proteins with multiple functional domains. This was most evident in the genes for signal transduction pathway and the related systems. Comparison of the putative amino acid sequences of the gene products with those in the Pfam database indicated that and PAS domains which may be involved in signal recognition were extremely abundant in Anabaena: 87 GAF domains in 62 ORFs and 140 PAS domains in 59 ORFs. As for the two-component signal transduction system, 73, 53, and 77 genes for simple sensory His kinases, hybrid His kinases and simple response regulators, respectively, many of which contained additional domains of diverse functions, were presumptively assigned. A total of 52 ORFs encoding putative Hanks-type Ser/Thr protein kinases with various domains such as WD-repeat, GAF and His kinase domains, as well as genes for presumptive protein phosphatases, were also identified. In addition, genes for putative transcription factors and for proteins in the cAMP signal transduction system harbored complex gene structures with multiple domains.

Prediction of higher order functional networks from genomic data

Post-genomics may be defined in different ways depending on how one views the challenges after the discovery of the genome. A traditional view is to follow the concept of the central dogma in molecular biology, namely from genome to transcriptome to proteome. Projects are ongoing to analyse gene expression profiles both at the mRNA and protein levels, and to catalogue protein 3D structure families, which will no doubt help the understanding of the information in the genome. However, once complete, such experimentally determined catalogues of genes, RNAs and proteins only tell us about the building blocks of life. They do not tell us much about how life operates as a system, such as higher order functional behaviours of the cell or the organism. Thus, an alternative view of post-genomics is to go up from the molecular level to the cellular level and eventually to still higher levels, i.e., the biological systems. Bioinformatics provides basic concepts as well as practical methods to integrate this view with the traditional view and to analyse complex interactions among building blocks and with dynamic environments.

Large-scale cDNA analysis of the maternal genetic information in the egg of Halocynthia roretzi for a gene expression catalog of ascidian development

The ascidian egg is a well-known mosaic egg. In order to investigate the molecular nature of the maternal genetic information stored in the egg, we have prepared cDNAs from the mRNAs in the fertilized eggs of the ascidian, Halocynthia roretzi. The cDNAs of the ascidian embryo were sequenced, and the localization of individual mRNA was examined in staged embryos by whole-mount in situ hybridization. The data obtained were stored in the database MAGEST (http://www.genome.ad.jp/magest) and further analyzed. A total of 4240 cDNA clones were found to represent 2221 gene transcripts, including at least 934 different protein-coding sequences. The mRNA population of the egg consisted of a low prevalence, high complexity sequence set. The majority of the clones were of the rare sequence class, and of these, 42% of the clones showed significant matches with known peptides, mainly consisting of proteins with housekeeping functions such as metabolism and cell division. In addition, we found cDNAs encoding components involved in different signal transduction pathways and cDNAs encoding nucleotide-binding proteins. Large-scale analyses of the distribution of the RNA corresponding to each cDNA in the eight-cell, 110-cell and early tailbud embryos were simultaneously carried out. These analyses revealed that a small fraction of the maternal RNAs were localized in the eight-cell embryo, and that 7.9% of the clones were exclusively maternal, while 40.6% of the maternal clones showed expression in the later stages. This study provides global insights about the genes expressed during early development.

Whole genome sequencing of meticillin-resistant Staphylococcus aureus

BACKGROUND

Staphylococcus aureus is one of the major causes of community-acquired and hospital-acquired infections. It produces numerous toxins including superantigens that cause unique disease entities such as toxic-shock syndrome and staphylococcal scarlet fever, and has acquired resistance to practically all antibiotics. Whole genome analysis is a necessary step towards future development of countermeasures against this organism.

METHODS

Whole genome sequences of two related S aureus strains (N315 and Mu50) were determined by shot-gun random sequencing. N315 is a meticillin-resistant S aureus (MRSA) strain isolated in 1982, and Mu50 is an MRSA strain with vancomycin resistance isolated in 1997. The open reading frames were identified by use of GAMBLER and GLIMMER programs, and annotation of each was done with a BLAST homology search, motif analysis, and protein localisation prediction.

FINDINGS

The Staphylococcus genome was composed of a complex mixture of genes, many of which seem to have been acquired by lateral gene transfer. Most of the antibiotic resistance genes were carried either by plasmids or by mobile genetic elements including a unique resistance island. Three classes of new pathogenicity islands were identified in the genome: a toxic-shock-syndrome toxin island family, exotoxin islands, and enterotoxin islands. In the latter two pathogenicity islands, clusters of exotoxin and enterotoxin genes were found closely linked with other gene clusters encoding putative pathogenic factors. The analysis also identified 70 candidates for new virulence factors.

INTERPRETATION

The remarkable ability of S aureus to acquire useful genes from various organisms was revealed through the observation of genome complexity and evidence of lateral gene transfer. Repeated duplication of genes encoding superantigens explains why S aureus is capable of infecting humans of diverse genetic backgrounds, eliciting severe immune reactions. Investigation of many newly identified gene products, including the 70 putative virulence factors, will greatly improve our understanding of the biology of staphylococci and the processes of infectious diseases caused by S aureus.