Methylmercury: a potential environmental risk factor contributing to epileptogenesis

Epilepsy or seizure disorder is one of the most common neurological diseases in humans. Although genetic mutations in ion channels and receptors and some other risk factors such as brain injury are linked to epileptogenesis, the underlying cause for the majority of epilepsy cases remains unknown. Gene-environment interactions are thought to play a critical role in the etiology of epilepsy. Exposure to environmental chemicals is an important risk factor. Methylmercury (MeHg) is a prominent environmental neurotoxicant, which targets primarily the central nervous system (CNS). Patients or animals with acute or chronic MeHg poisoning often display epileptic seizures or show increased susceptibility to seizures, suggesting that MeHg exposure may be associated with epileptogenesis. This mini-review highlights the effects of MeHg exposure, especially developmental exposure, on the susceptibility of humans and animals to seizures, and discusses the potential role of low level MeHg exposure in epileptogenesis. This review also proposes that a preferential effect of MeHg on the inhibitory GABAergic system, leading to disinhibition of excitatory glutamatergic function, may be one of the potential mechanisms underlying MeHg-induced changes in seizure susceptibility.     

Biological aspects of sexual desire in women

The physiology of sexual desire in women is poorly understood. There is evidence that androgens stimulate sexual desire and prolactin may be inhibitory. Oestrogens probably do not have a direct effect of female sexual desire but may indirectly increase it in oestrogen-deficient women by promoting the feelings of femininity. Little is known about the central neurotransmitters that influence sexual desire but it is likely that 5-hydroxytryptamine is inhibitory. A better understanding of the hormonal and chemical control of sexual desire in women may open new avenues to the treatment of lack of desire which is a common presenting symptom.     

Reduced sexual desire in a random sample of Norwegian couples

Abstract

The purpose of this study was to analyse reduced sexual desire in Norwegian heterosexual couples and to identify factors associated with loss of sexual desire in both men and women. The study comprises a sample of 399 couples (798 individuals) between 22 to 67 years of age. Data were collected by the means of self-administered postal questionnaires. The majority of the couples (59%) did not report distressing problems related to loss of sexual desire. In 26% of the couples the female partner had experienced distressing loss of sexual desire; in 8% of the couples the male partner did, and in 8% of the couples both experienced distressing problems. Most of the men and women who had sexual desire problems believed their loss of sexual desire was related to stress, disease, or “other” factors. Reduced capacity for sexual arousal was the best predictor of loss of desire in both genders. Among women, negative work-to-home interference was related to loss of sexual desire. It seems reduced sexual desire may represent a new area of public health concern in Norway.     

Alcohol as a risk factor for HIV transmission among American Indian and Alaska Native drug users

Quantitative alcohol interviews conducted as part of the National Institute on Drug Abuse (NIDA) Native American Supplement revealed very high rates of alcohol use among American Indian and Alaska Native active crack and injection drug users (IDUs). Of 147 respondents who completed the alcohol questionnaire, 100& percent had drunk alcohol within the past month, almost 42& percent reported that they drank every day, and 50& percent drank until they were drunk one-half of the time or more. Injection drug users (IDUs) demonstrated the highest frequency and quantity of alcohol use in the past 30 days. A significant positive association was also found between crack and alcohol use in the past 48 hours (c(2)=5.30, p<.05). Finally, those claiming more episodes of using alcohol before or during sex, reported significantly more events of unprotected sexual intercourse. Qualitative data from all four sites corroborated these quantitative findings. Many individuals also reported episodes of blacking out while drinking, and learned later that they had had unprotected sex with complete strangers or individuals they would not otherwise accept as partners. Implications of these findings for HIV/AIDS prevention efforts are addressed.     

Evidence-based treatments for low sexual desire in women

Low sexual desire is the most common sexual complaint in women, with multinational studies finding that at least a third of women experience low sexual desire. No single etiology for the development of Female Sexual Interest/Arousal Disorder, the diagnosis laid out by the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders, has been established. There has been considerable interest in pharmacological approaches to improving low desire, and agents targeting a range of neurotransmitters have been examined. To date, only flibanserin, a centrally acting medication targeting the serotonin, dopamine, and norepinephrine systems, has been approved by the Food and Drug Administration (FDA). Despite statistically significant effects on sexual desire, sexual distress, and sexually satisfying events, side-effects are significant, and flibanserin is completely contraindicated with alcohol. As such, there has been renewed interest in advancing the science of psychological approaches to low desire, including cognitive behavioral and mindfulness therapies.     

Review of psychological factors in low sexual desire

During the last decade an increasing number of papers have been published on low sexual desire (LSD). The purpose of this paper is to highlight some important issues related to LSD and critically examine what has been reported in the literature. Problems related to assessment and treatment are presented. The author suggests that research is needed on the characteristics of the subjects suffering from LSD to have a better understanding of this complex sexual problem and to develop effective methods of assessment and treatment.     

Brain processing of visual sexual stimuli in men with hypoactive sexual desire disorder

Although hypoactive sexual desire disorder (HSDD) is a common condition and has long been hypothesized to result from malfunctions of the cerebral control mechanisms that adjust the level of sexual motivation, very little is known about the pathophysiology of this disorder. The primary objective was to identify in patients with HSDD brain regions where functional perturbations disrupt the regulation of sexual motivation. We used positron emission tomography to compare seven male patients with HSDD with eight healthy men on their regional cerebral blood flow responses to visual sexual stimuli (VSS) of graded intensity. Statistical Parametric Mapping was used to locate brain regions that demonstrated a differential activation (or deactivation) across the groups. Whereas in control subjects the medial orbitofrontal cortex showed a deactivation in response to VSS, in HSDD patients there was an abnormally maintained activity of this region, which has been implicated in the inhibitory control of motivated behavior. By contrast, the reverse pattern-activation in control subjects, deactivation or unchanged activity in patients-was found in the secondary somatosensory cortex and inferior parietal lobules, regions mediating emotional and motor imagery processes, as well as in those areas of the anterior cingulate gyrus and of the frontal lobes that are involved in premotor processes.     

Sexual compatibility and the sexual desire-motivation relation in females with hypoactive sexual desire disorder

Fifty-four female participants with hypoactive sexual desire disorder supplied daily reports of their sexual desire and motivation. The relation between desire and motivation remained statistically significant when controlling for sexual compatibility, sexual stress, sexual fantasy, and marital and sexual satisfaction. Findings suggest that (a) women higher in sexual compatibility experience greater sexual motivation regardless of their marital and sexual satisfaction, their sexual desire intensity, and depressive symptomatology; and (b) the relation between sexual compatibility and sexual desire is mediated by the propensity of those women high in sexual compatibility to have greater marital and sexual satisfaction. Within-subject analyses that controlled for autocorrelation and linear trends in the time series revealed that 40% of the women experienced significantly higher sexual motivation on greater sexual desire days. A discussion of these findings and evidence for the addition of sexual motivation as a distinct phase in the human sexual response cycle are explored.     

Facilitators and barriers affecting sexual desire in elderly Iranian women: a qualitative study

ABSTRACT

Elderly people are very common perceived as asexual but some studies have reported some variations. However, very little research has been done to determine the facilitators and barriers that affect sexuality, especially in relation to elderly women. This study was undertaken to explore perceptions of sexuality among a selection of married older women in Iran in terms of facilitators and barriers. Accordingly, a study was done on 27 married women, older than 60 years. Qualitative content analysis was used to identify four distinct subthemes that served as facilitators of sexual desire. These were determined as life satisfaction, favourable outcome, spouse's characteristics, and a sense of duty. Four other subthemes were determined as barriers to sexual desire; namely physical weakness, evolving emotions, a sense of taboo, and a sense of insecurity. All these variables appeared rooted in religious teachings, social stereotypes, or cultural traditions that constituted women's perceptions of themselves as elderly married women. Further study is recommended on elderly people that includes participants of both sexes and with different marital statuses.     

Heterogeneity between hippocampal and septal astroglia as a contributing factor to differential in vivo AMPA excitotoxicity

Astroglial participation in the regional differences of vulnerability to alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-induced neurodegeneration was investigated in the rat hippocampus and medial septum using L-alpha-aminoadipate (alpha-AA) as a specific astroglial toxin. alpha-AA was microinjected in the hippocampus and the medial septum and a time-course study was carried out between 2 hr and 3 days. When compared to controls, microinjection of alpha-AA in the hippocampus induced within 3 days a reversible loss of glial fibrillary acidic protein (GFAP) immunostaining and a microglial reaction without any neuronal loss, whereas in the medial septum it caused no effects on astroglial, microglial, or neuronal populations. Differences in hippocampus and medial septum vulnerability were also evidenced when alpha-AA was co-injected with AMPA and neurodegeneration was assessed in terms of neuronal loss, glial reactions, calcification, and atrophy of the area. In the hippocampus, alpha-AA increased AMPA excitotoxicity with marked disorganization of all hippocampal subfields, increased neuronal loss, a more important astroglial reaction, a larger area of microgliosis, and a greater abundance of calcium deposits. By contrast, in the medial septum alpha-AA did not modify any parameter of the AMPA-induced lesion. In conclusion, the presence of different astroglial populations in hippocampus and medial septum results in a different participation to AMPA excitotoxicity that may determine, at least in part, the specific regional vulnerability to neurodegeneration.     

Impulsiveness as a factor in sexual offending by people with mild intellectual disability

Background It has been suggested that sexual offending by people with intellectual disability (ID) results from a pattern of impulsive behaviour that is consistent with psychosocial disadvantage, rather than sexual deviancy. This study aimed to explore this hypothesis by assessing levels of impulsiveness in sexual offenders, non‐sexual offenders and non‐offenders with mild ID. Method Impulsiveness was assessed using a modified version of the Barratt Impulsiveness Scale (11th edition). Total impulsivity scores were compared between sexual offenders, non‐sexual offenders and non‐offenders, all with mild ID. Results There was a significant difference in the levels of impulsiveness between sexual offenders and non‐sexual offenders with ID (t = 2.83, P < 0.01). The sexual offenders were less impulsive than non‐sexual offenders. Conclusions This study did not support the hypothesis that sexual offending by people with ID is better explained by impulsive behaviour rather than sexual deviancy. It supports recent findings that among the general population, sexual offenders are less impulsive than controls and violent offenders.     

Procalcitonin as a potential predicting factor for prognosis in bacterial meningitis

We investigated the potential role of serum procalcitonin in differentiating bacterial meningitis from viral meningitis, and in predicting the prognosis in patients with bacterial meningitis. This was a retrospective study of 80 patients with bacterial meningitis (13 patients died). In addition, 58 patients with viral meningitis were included as the disease control groups for comparison. The serum procalcitonin level was measured in all patients at admission. Differences in demographic and laboratory data, including the procalcitonin level, were analyzed between the groups. We used the mortality rate during hospitalization as a marker of prognosis in patients with bacterial meningitis. Multiple logistic regression analysis showed that high serum levels of procalcitonin (>0.12 ng/mL) were an independently significant variable for differentiating bacterial meningitis from viral meningitis. The risk of having bacterial meningitis with high serum levels of procalcitonin was at least 6 times higher than the risk of having viral meningitis (OR = 6.76, 95% CI: 1.84–24.90, p = 0.004). In addition, we found that high levels of procalcitonin (>7.26 ng/mL) in the blood were an independently significant predictor for death in patients with bacterial meningitis. The risk of death in patients with bacterial meningitis with high serum levels of procalcitonin may be at least 9 times higher than those without death (OR = 9.09, 95% CI: 1.74–47.12, p = 0.016). We found that serum procalcitonin is a useful marker for differentiating bacterial meningitis from viral meningitis, and it is also a potential predicting factor for prognosis in patients with bacterial meningitis.     

Poor sleep as a potential causal factor in aggression and violence

Clinical observations suggest that sleep problems may be a causal factor in the development of reactive aggression and violence. In this review we give an overview of existing literature on the relation between poor sleep and aggression, irritability, and hostility. Correlational studies are supporting such a relationship. Although limited in number, some studies suggest that treatment of sleep disturbances reduces aggressiveness and problematic behavior. In line with this is the finding that sleep deprivation actually increases aggressive behavior in animals and angriness, short-temperedness, and the outward expression of aggressive impulses in humans. In most people poor sleep will not evoke actual physical aggression, but certain individuals, such as forensic psychiatric patients, may be particularly vulnerable to the emotional dysregulating effects of sleep disturbances. The relation between sleep problems and aggression may be mediated by the negative effect of sleep loss on prefrontal cortical functioning. This most likely contributes to loss of control over emotions, including loss of the regulation of aggressive impulses to context-appropriate behavior. Other potential contributing mechanisms connecting sleep problems to aggression and violence are most likely found within the central serotonergic and the hypothalamic-pituitary-adrenal-axis. Individual variation within these neurobiological systems may be responsible for amplified aggressive responses induced by sleep loss in certain individuals. It is of great importance to identify the individuals at risk, since recognition and adequate treatment of their sleep problems may reduce aggressive and violent incidents.     

The role of fellatio in marital sexuality: An examination of sexual compatibility and sexual desire

This study assesses the role of fellatio in moderating an association between wives' sexual compatibility with their husbands and husbands' and wives' sexual desire towards each other. Participants were 73 non-distressed, sexually functional, married couples. Hierarchical regression analyses indicate that the Wives' Sexual Compatibility With Husbands X Fellatio Classification interaction contributed unique variance to the prediction of both husbands' and wives' sexual desire towards each other, after wives' sexual compatibility with husbands, fellatio classification, and relationship length were controlled. For those women who describe fellatio to be a satisfying experience, Pearson correlations indicated that wives' sexual compatibility with husbands correlated positively with husbands' and wives' sexual desire for each other. These findings did not hold true for those women who described fellatio as distatisfying.     

Sex steroids and sexual desire in a man with a novel mutation of aromatase gene and hypogonadism

Sexual behavior was investigated by a sexological interview in a man with aromatase deficiency and hypogonadism. The study was performed at the end of a long testosterone treatment, during transdermal estradiol treatment and during estradiol and testosterone associated treatment. Sexual behavior did not show abnormalities. As assessed by a sexological interview and by a sexological questionnaire gender-identity was male, sexual orientation was heterosexual and libido was normal. Sexual function was limited to masturbation and was seemingly unaffected by testosterone or estradiol alone; only the associated treatment induced a great increase in libido and in frequency of masturbation and sexual fantasies when both testosterone and estradiol reached the range of normality. Sexual behavior is mainly under the control of cognitive functions in men, but sex steroids may modulate some aspects of male sexuality. Our findings suggest that in men estrogens could play a role in sexual activity.