Biological signalling supports biotechnology - Pulsed electric fields extract a cell-death inducing factor from Chlorella vulgaris.

Compared to mechanical extraction methods, pulsed electric field (PEF) treatment provides an energy-efficient and gentle alternative. However, the biological processes involved are poorly understood. The unicellular green microalga Chlorella vulgaris was used as model organism to investigate the effect of PEF treatment on biological cells. A viability assay using fluorescein diacetate measured by flow cytometry was established. The influence of developmental stage on viability could be shown in synchronised cultures when applying PEF treatment with very low specific energies where one part of cells undergoes cell death, and the other part stays viable after treatment. Reactive oxygen species generation after similar low-energy PEF treatment could be shown, indicating that PEFs could act as abiotic stress signal. Most importantly, a cell-death inducing factor could be extracted. A water-soluble extract derived from microalgae suspensions incubated for 24 h after PEF treatment caused the recipient microalgae to die, even though the recipient cells had not been subjected to PEF treatment directly. The working model assumes that low-energy PEF treatment induces programmed cell death in C.vulgaris while specifically releasing a cell-death inducing factor. Low-energy PEF treatment with subsequent incubation period could be a novel biotechnological strategy to extract soluble proteins and lipids in cascade process.

Novel parameters of global and regional mitral annulus geometry in man: comparison between normals and organic mitral regurgitation, before and after mitral valve repair.

AIMS: The mitral annulus (MA) saddle shape is complex but vital for a normal functioning mitral apparatus. Although conventional parameters of MA geometry such as area and height are helpful, they fall short of describing its complex regional geometry. METHODS AND RESULTS: In this prospective study, novel parameters of MA curvature and torsion were derived from three-dimensional (3D) transoesophageal echocardiography. These quantitative indices were computed in 15 patients with normal valves (age 53 ± 8 years) and in 15 patients with organic significant mitral regurgitation (MR, age 66 ± 11 years), before and after mitral valve repair (MVR). The MA was traced and modelled in mid- and end-systole. Curvature and torsion were computed at 500 points across the MA to derive regional and global indices. Overall, patients with organic MR presented the smallest global curvature and torsion; this decrease in curvature and torsion reflects a loss of tonicity of the MA tissue. These changes were largely corrected with MVR surgery, to higher values, compared with normals. The regional analysis revealed similar trends. The maximal MA curvature was found to be at the MA 'anterior horn', whereas the MA 'posterior horn' had the lowest curvature values. CONCLUSION: Novel MA parameters of curvature and torsion can be computed from 3D echocardiography and provide quantitative characteristics of dynamic regional MA geometry. In patients with organic MR, the reduced regional and global curvatures improve following surgical MVR. These quantitative parameters may help further refine the quantitative description of MA geometry in various mitral valve pathologies and after MVR.

Validation of the new consensus criteria for the diagnosis of corticobasal degeneration.

BACKGROUND: Corticobasal degeneration (CBD) is a complex neurodegenerative disorder. Accurate diagnosis is increasingly important, with the advent of clinical trials of drugs aimed at modifying the underlying tau pathology. CBD often presents with a 'corticobasal syndrome' including impairments of movement and cognition. However, patients with similar corticobasal syndromes can have neurodegenerative pathologies that are not CBD. In addition, patients with CBD may present with aphasia or behavioural change. The clinical diversity of CBD and mimicry by non-CBD pathologies hinders accurate diagnosis. METHODS: We applied the new consensus criteria of Armstrong and colleagues et al 1 to a cohort of patients with detailed longitudinal clinical evaluation and neuropathology. RESULTS: In patients with pathologically confirmed CBD, accuracy of diagnosis was similar under the new and previous criteria: 9/19 (47%) met criteria for probable CBD at presentation, 13/19 (68%) at last clinical assessment. Patients with a corticobasal syndrome but without CBD pathology all (14/14) met the new diagnostic criteria of probable or possible CBD, demonstrating that the new criteria lacks the necessary specificity for an accurate ante mortem clinical diagnosis of CBD. None of the clinical features used in the new criteria were more common in the patients with CBD pathology (n=19) than without (n=14). CONCLUSIONS: The Armstrong criteria usefully broadens the recognised clinical phenotype of CBD but does not sufficiently improve the specificity of diagnosis to increase the power of clinical trials or targeted applications of tau-based disease-modifying therapies. Further work is required to show whether biomarkers could be more effective than clinical signs in the diagnosis of CBD.

CADASIL presenting with a behavioural variant frontotemporal dementia phenotype.

The behavioural variant of frontotemporal dementia (bvFTD) is characterised by personality change with a decline in cognition. We describe two patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukencephalopathy (CADASIL) who presented with behavioural phenotypes similar to bvFTD. The first patient presented with progressive personality and behavioural change, had florid white matter hyperintensity, and had a novel missense mutation C366W in exon 7 of the Notch3 gene. The second patient presented with progressive memory impairment and marked personality changes after a transient ischaemic attack. In this second patient, the radiological features were subtle and only the family history of stroke prompted testing for CADASIL using Notch3 genotyping. We present these patients to demonstrate that CADASIL may mimic bvFTD, with little clinical or radiological evidence to distinguish the two. CADASIL may be an under-recognised diagnosis in apparent bvFTD. Screening Notch3 in a substantial and unselected cohort of frontotemporal dementia patients might be appropriate to investigate this possibility.

Conflicting perceptions between health care professionals and patients on the psychological morbidity following miscarriage.

BACKGROUND: Miscarriage is common and may result in significant psychological morbidity for women. Recent research has revealed that health care professionals often tend to neglect this factor. This negligence may lead to delayed diagnosis and appropriate care. AIMS: To assess health care professionals' and patients' attitudes towards the psychological impact of miscarriage. METHODS: A prospective, cross-sectional survey of nearly 3000 subjects was conducted. Of these, 1269 were health care professionals and 1519 were pregnant women or their spouses. Their perceptions of the psychological impact of miscarriage, in comparison with postnatal depression were studied. RESULTS Health care professionals were less aware of the psychological impact of miscarriage compared with postnatal depression (91.9 vs 98.4%, P = 0.02). Furthermore, they believed that the psychological impact of miscarriage was less than that of postnatal depression (79.9 vs 88.9%, P < 0.001). However, more patients believed that psychological impact after miscarriage can seriously affect women (59.0 vs for health care professionals 38.3%, P < 0.001). A higher proportion of patients compared with health care professionals (85.2 vs 74.3%, P < 0.001) believed that routine psychological support should be provided after miscarriage, but few agreed that primary health professionals were the most suitable people to provide this care although most health care professionals thought this to be appropriate (9.1 vs 59.7%, P < 0.001). CONCLUSION: Health care professionals should be more aware of the psychological morbidity associated with miscarriage and also be sensitive to a currently unmet need for psychological care.

Detecting postnatal depression in Chinese men: a comparison of three instruments.

Postnatal depression affects both men and women. The detection of postnatal depression is important, yet there are few validated screening tools on Chinese men. The goals of the present study were to compare the psychometric properties of the Edinburgh Postnatal Depression Scale (EPDS), the Beck Depression Inventory (BDI), and the Patient Health Questionnaire - Depression Module (PHQ-9) in screening for postnatal depression among Chinese fathers in Hong Kong. The prevalence of depression at 8 weeks postpartum was also estimated. A prospective cohort of 551 men completed the EPDS, BDI, and PHQ-9 at 8 weeks postpartum. Clinical diagnosis of depression was established with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), non-patient version (SCID-NP). The criterion validity of the instruments was evaluated against this clinical diagnosis. The EPDS was significantly more accurate than the BDI and PHQ-9 in detecting postnatal depression among Chinese men. With a cut-off score of 10 or more, the EPDS has a sensitivity of 91%, specificity of 97%, positive predictive value of 57%, and negative predictive value of 99%. Approximately 3.1% men met the DSM-IV criteria for depression at 8 weeks postpartum. The prevalence rate of postnatal depression in Chinese men is comparable to their Western counterparts. The Chinese EPDS is a valid instrument for detecting postnatal depression in men. It could be applied as a supplementary assessment tool in Chinese fathers who may be reluctant to disclose their depressive symptoms in face-to-face interviews.

Antenatal taboos among Chinese women in Hong Kong.

OBJECTIVE: to identify the antenatal taboos commonly practised by pregnant Hong Kong Chinese women; to explore the health beliefs behind these taboos; and to examine how pregnant women perceived and reacted to the cultural tradition. DESIGN: general ethnography and in-depth interviews, followed by a quantitative self-reported survey. SETTING: Antenatal clinic of a university-affiliated hospital in Hong Kong. PARTICIPANTS: consecutive samples of 60 women for in-depth interviews, and 832 women for the survey. MEASUREMENTS: an inventory on the adherence and attitude towards antenatal taboos, and the Beck Depression Inventory that measures severity of depression. FINDINGS: antenatal taboos were still commonly observed by contemporary Chinese women. Miscarriage, fetus malformation and fetal ill-health were the key cultural fears that drove contemporary Chinese women to observe the traditional taboos. About one-quarter and one-tenth of the women, respectively, felt unhappy and disputed with their families about the taboos. These women had significantly higher levels of depression in late pregnancy and during childbirth. IMPLICATIONS FOR PRACTICE: health-care practitioners should be aware of the benefits and risks of traditional antenatal taboos on maternal health. Although some taboos can be socio-morally protective, the tension created by the observation of cultural tradition in modernity may impair maternal psychological well-being. Health-care providers in Western countries should be vigilant of the complex cultural tension faced by migrant Chinese mothers.

Fetal methylmercury exposure as measured by cord blood mercury concentrations in a mother-infant cohort in Hong Kong.

This study was designed to examine newborn infants in Hong Kong prenatally exposed to levels of methylmercury considered to increase risk of neurotoxic effects and to examine subject characteristics that modify the degree of prenatal mercury exposure. Mercury concentrations in 1057 sets of maternal and cord blood samples and 96 randomly selected maternal hair samples were measured. Subject characteristics were measured or collected by questionnaire. Of the 1057 cord blood samples collected only 21.6% had mercury concentrations less than 29 nmol/L (5.8 micro g/L). Median maternal hair mercury concentration was 1.7 ppm. The geometric mean cord to maternal blood mercury ratio was 1.79 to 1. Increasing maternal fish consumption and maternal age were found to be associated with increased cord blood mercury concentrations. Marine fish consumption increased cord blood mercury concentrations more than freshwater fish (5.09%/kg vs 2.86%/kg). Female babies, maternal alcohol consumption and increasing maternal height were associated with decreased cord blood mercury concentrations. Pregnant women in Hong Kong consume large amounts of fish and as a result, most of their offspring have been prenatally exposed to moderately high levels of mercury. In this population, pregnant women should choose freshwater over marine fish and limit fish consumption.

Psychological responses of pregnant women to an infectious outbreak: a case-control study of the 2003 SARS outbreak in Hong Kong.

OBJECTIVE: The aim of the present study was to examine the behavioral and psychological responses of pregnant women during the 2003 severe acute respiratory syndrome (SARS) outbreak in Hong Kong. METHODS: Ethnographic interviews were first conducted to identify the common psychological and behavioral responses to the outbreak. This was followed by a case-control study of 235 consecutive pregnant women recruited during the SARS epidemic, and a historical cohort of 939 pregnant women recruited a year before the outbreak. Both cohorts completed standardized rating scales on depression, anxiety, and social support. RESULTS: Women in the SARS cohort adopted behavioral strategies to mitigate their risk of contracting infection. However, pregnant women tended to overestimate the risk of contracting SARS and nearly a third of the women were homebound. The anxiety level of the SARS cohort was slightly higher than that of the pre-SARS control. No statistical difference was found between the depression levels of the two cohorts. CONCLUSION: The improved social support experienced by pregnant women during SARS might have buffered the stress associated with an outbreak. However, clinicians should monitor for overestimation of infectious risk among pregnant women.

A prevalence study of antenatal depression among Chinese women.

BACKGROUND: There has thus far been no empirical research on the occurrence of antenatal psychiatric morbidity in Chinese population. Epidemiological studies in western societies generally show that depressive episodes occur in 10-20% of pregnant women. Longitudinal studies have demonstrated that antenatal depression is one of the most powerful predictors of postnatal depression. There is also a growing literature that shows that antenatal psychological distress can adversely affect maternal and foetal well being. METHODS: At 38 weeks of pregnancy, 238 consecutive women were invited to return for psychiatric assessment. The participants were interviewed using the non-patient version of the Structured Clinical Interview for DSM-IV (SCID-NP). RESULTS: Seventy women (29%) declined to participate, and another 11 (5%) defaulted the SCID interview. Among the 157 women interviewed, the 1-month prevalence of antenatal depression was 4.4%. The 1-month prevalence of all psychiatric diagnoses was 6.4%. The prevalence of antenatal depression and all psychiatric diagnoses for the entire pregnancy was 6.4% and 8.3%, respectively. LIMITATIONS: About a third of eligible subjects did not participate in the study. CONCLUSIONS: A significant proportion of Chinese women suffer from psychiatric morbidity during pregnancy. Depressive disorders are by far the commonest morbidity in the study population. Given the scope of the morbidity and the potential impact on obstetric and neonatal outcomes, early screening and treatment are warranted.

Ethnoepidemiology of postnatal depression. Prospective multivariate study of sociocultural risk factors in a Chinese population in Hong Kong.

BACKGROUND: Although there have been many studies of the biological and psychosocial causations of postnatal depression, studies of sociocultural risk factors are rare. AIMS: To investigate the sociocultural risk factors of postnatal depression using ethnographically informed epidemiological methods. METHOD: A total of 959 women were assessed at their first ante-partum visit (baseline), in the third trimester, immediately after delivery, and 3 months postpartum. Six domains of risk factors were examined. The dependent variable was postnatal depression (as defined by the Edinburgh Postnatal Depression Scale) at 3 months post-partum. RESULTS: Conflict with mother-in-law, marital dissatisfaction, past depression and antenatal depression independently predicted the occurrence of postnatal depression. The cultural practice of peiyue - a Chinese post-partum custom of mandated family support - was associated with better social support and a slightly lower risk of postnatal depression. CONCLUSIONS: Sociocultural aspects of the immediate puerperium shape maternal emotional well-being. In-law conflict is an important source of household distress in many Asian societies. The findings have implications for clinical practice and future studies.

Postdelivery screening for postpartum depression.

OBJECTIVE: Postpartum depression (PPD) is a serious psychiatric disorder affecting 10% to 20% of women after childbirth. Research has shown that systematic screening for PPD using self-report questionnaires helps improve the identification of PPD and expedite treatment. Most studies on PPD screening have been conducted in the second and third postpartum months; little is known about whether PPD screening can be carried out on the days immediately after delivery. METHODS: A prospective cohort of 145 women completed the Edinburgh Postnatal Depression Scale (EPDS), Beck Depression Inventory (BDI), and General Health Questionnaire (GHQ) within 2 days of delivery. Six weeks after delivery, the participants were interviewed by a psychiatrist, who used the Structured Clinical Interview for DSM-III-R (SCID, nonpatient version) to establish the diagnosis. The psychometric performance of the EPDS, BDI, and GHQ in detecting PPD was assessed using the SCID diagnosis as the gold standard. RESULTS: When the cutoffs of the EPDS, BDI, and GHQ were lowered to achieve a sensitivity of 80%, the positive predictive values of these scales were to 13%, 18%, and 21%, respectively. When the cutoffs were raised to achieve a positive predictive value of 50%, the sensitivity rates were 6% (EPDS), 14% (GHQ), and 36% (BDI). CONCLUSIONS: When commonly used depression rating scales were administered to identify PPD immediately after delivery, their psychometric properties were unsatisfactory. Healthcare providers should not screen for PPD in the first few days after delivery.

Evaluation of alternative oil spill cleanup techniques in a Spartina alterniflora salt marsh.

Three oil spill situations which cause long-term impact were simulated in 1 m(2) salt marsh plots to evaluate the effectiveness of alternative cleanup techniques at removing oil and reducing damage to Spartina alterniflora. Cleanup techniques, implemented 18-24 h after oiling, were not effective at removing oil after sediment penetration. When oil remained on the sediment surface, flushing techniques were most effective at removal, reducing levels of added oil by 73% to 83%. The addition of dispersant to the flushing stream only slightly enhanced oil removal. Clipping of vegetation followed by sorbent pad application to sediment was moderately effective, reducing added oil by 36% to 44%. In contrast to flushing and clipping, burning increased the amount of oil in sediment by 27% to 72%. Although flushing and clipping were effective at oil removal, neither technique reduced initial damage to plants or enhanced long-term recovery. While flushed plots sustained no additional plant damage due to cleanup, clipped and burned plots sustained additional initial plant damage. Based on these results, first considerations should be given to natural tidal flushing as the means to remove oil, especially in salt marshes subject to ample tidal inundation. Although our results do not support cleanup in salt marshes with ample tidal inundation, low pressure flushing may be warranted when fuel oils or large quantities of crude oil impact salt marshes subject to reduced tidal flushing. Flushing, when warranted, should be initiated prior to oil penetration into the substrate. Clipping may be considered as a cleanup response only when heavy oil cannot be effectively removed from vegetation by flushing. Burning is not recommended because it enhances oil penetration into sediment and causes substantial initial plant damage.

Short-term effects of South louisiana and kuwait crude oils on glucose utilization by marine bacterial populations.

Two crude oils, South Louisiana and Kuwait, were examined for their impact on glucose utilization by bacterial populations from the Gulf of Mexico. The uptake and mineralization of [U-C]glucose was assayed after a 4- to 23-h exposure to various concentrations of added crude oil (0, 0.001, 0.01, and 0.1% [vol/vol]). The effects of oil were determined in a total of 15 sediment and 13 water samples collected from offshore, open-bay, and salt marsh environments. The utilization of glucose by bacterial populations usually was not affected by added oil; in 10 sediment and 11 water samples, oil had no significant effect on either glucose uptake or mineralization. Stimulation by oil was recorded in four sediment samples. Oil inhibition occurred in one sediment and two water samples, but only in the presence of the highest concentration of added oil, i.e., 0.1%. Our data suggest that short-term exposure to either South Louisiana or Kuwait crude oil, even at 0.1%, usually has no toxic effect on glucose utilization by marine bacterial populations.