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Cortisol and oxytocin have been shown to interact in both the regulation of stress responses and in memory function. In the present study we administered cortisol to 35 healthy female subjects in a within-subject double-blind placebo-controlled design, while measuring oxy-tocin levels, adrenocorticotropic hormone (ACTH) levels, and free recall of pleasant and of unpleasant words. We found that cortisol administration suppressed ACTH levels and (1) induced a decrease in oxytocin associated with ACTH suppression and (2) an increase in oxytocin that was independent from ACTH suppression. This cortisol-induced increase in plasma oxytocin was associated with a selective decrease in immediate free recall of unpleasant words from primacy positions.The present results add to evidence that cortisol-induced increases in oxytocin could mediate some of the effects of stress and cortisol on memory, and possibly play a role in the regulation of the hypothalamo-pituitary-adrenal stress response. This mechanism could significantly impact affective and social behaviors, in particular during times of stress.

The manner in which individuals recall an autobiographical positive life event has affective consequences. Two studies addressed the processing styles during positive memory recall in a non-clinical sample. Participants retrieved a positive memory, which was self-generated (Study 1, n = 70) or experimenter-chosen (i.e., academic achievement, Study 2, n = 159), followed by the induction of one of three processing styles (between-subjects): in Study 1, a "concrete/imagery" vs. "abstract/verbal" processing style was compared. In Study 2, a "concrete/imagery," "abstract/verbal," and "comparative/verbal" processing style were compared. The processing of a personal memory in a concrete/imagery-based way led to a larger increase in positive affect compared to abstract/verbal processing in Study 1, as well as compared to comparative/verbal thinking in Study 2. Results of Study 2 further suggest that it is making unfavorable verbal comparisons that may hinder affective benefits to positive memories (rather than general abstract/verbal processing per se). The comparative/verbal thinking style failed to lead to improvements in positive affect, and with increasing levels of depressive symptoms it had a more negative impact on change in positive affect. We found no evidence that participant's tendency to have dampening thoughts in response to positive affect in daily life contributed to the affective impact of positive memory recall. The results support the potential for current trainings in boosting positive memories and mental imagery, and underline the search for parameters that determine at times deleterious outcomes of abstract/verbal memory processing in the face of positive information.

Cortisol and oxytocin have been shown to interact in both the regulation of stress responses and in memory function. In the present study we administered cortisol to 35 healthy female subjects in a within-subject double-blind placebo-controlled design, while measuring oxytocin levels, adrenocorticotropic hormone (ACTH) levels, and free recall of pleasant and of unpleasant words. We found that cortisol administration suppressed ACTH levels and (1) induced a decrease in oxytocin associated with ACTH suppression and (2) an increase in oxytocin that was independent from ACTH suppression. This cortisol-induced increase in plasma oxytocin was associated with a selective decrease in immediate free recall of unpleasant words from primacy positions. The present results add to evidence that cortisol-induced increases in oxytocin could mediate some of the effects of stress and cortisol on memory, and possibly play a role in the regulation of the hypothalamo-pituitary-adrenal stress response. This mechanism could significantly impact affective and social behaviors, in particular during times of stress.

The manner in which individuals recall an autobiographical positive life event has affective consequences. Two studies addressed the processing styles during positive memory recall in a non-clinical sample. Participants retrieved a positive memory, which was self-generated (Study 1, n = 70) or experimenter-chosen (i.e., academic achievement, Study 2, n = 159), followed by the induction of one of three processing styles (between-subjects): in Study 1, a "concrete/imagery" vs. "abstract/verbal" processing style was compared. In Study 2, a "concrete/imagery," "abstract/verbal," and "comparative/verbal" processing style were compared. The processing of a personal memory in a concrete/imagery-based way led to a larger increase in positive affect compared to abstract/verbal processing in Study 1, as well as compared to comparative/verbal thinking in Study 2. Results of Study 2 further suggest that it is making unfavorable verbal comparisons that may hinder affective benefits to positive memories (rather than general abstract/verbal processing per se). The comparative/verbal thinking style failed to lead to improvements in positive affect, and with increasing levels of depressive symptoms it had a more negative impact on change in positive affect. We found no evidence that participant's tendency to have dampening thoughts in response to positive affect in daily life contributed to the affective impact of positive memory recall. The results support the potential for current trainings in boosting positive memories and mental imagery, and underline the search for parameters that determine at times deleterious outcomes of abstract/verbal memory processing in the face of positive information.

Lateral flow (immuno)assays are currently used for qualitative, semiquantitative and to some extent quantitative monitoring in resource-poor or non-laboratory environments. Applications include tests on pathogens, drugs, hormones and metabolites in biomedical, phytosanitary, veterinary, feed/food and environmental settings. We describe principles of current formats, applications, limitations and perspectives for quantitative monitoring. We illustrate the potentials and limitations of analysis with lateral flow (immuno)assays using a literature survey and a SWOT analysis (acronym for 'strengths, weaknesses, opportunities, threats'). Articles referred to in this survey were searched for on MEDLINE, Scopus and in references of reviewed papers. Search terms included 'immunochromatography', 'sol particle immunoassay', 'lateral flow immunoassay' and 'dipstick assay'.

This thesis is aimed at the development of a dry reagent immunoassay of progesterone in cow's milk. Progesterone is a steroid hormone and regulates ovulation in female mammals. The concentration of progesterone in blood and in milk is in accordance with the reproductive cycle of the individual female. When items related to reproduction need to be addressed, an assay of progesterone is often the method of choice. In the dairy industry, progesterone tests in bovine milk are used as a non-invasive method for determination of the reproductive status of the cow. To minimize user handling, the format of a dry reagent assay is chosen. This format can be automated, gives results fast, and investments and disposables are low-cost. These requirements are obligatory as preferably these test are performed at every milking., Door allerlei oorzaken is het steeds moeilijker geworden om het juiste tijdstip van inseminatie te bepalen. Het is belangrijk om het juiste tijdstip van inseminatie van koeien te bepalen om te tussenkalftijd weer naar aanvaardbare proporties terug te krijgen. Progestron is een indicator van de vruchtbaarheid van een koe. In het proefschrift worden diverse mogelijkheden onderzocht om progestron in melk aan te tonen

Several aspects of the development of competitive lateral flow immunoassays (LFIAs) are described. The quantitation of progesterone is taken as an example. The LFIA format consisted of a nitrocellulose membrane spotted with various progesterone conjugates as the test line. A mixture of primary antibody and secondary antibody adsorbed to colloidal carbon was used for signal generation. A digital scanner and dedicated software were used to quantitate the response. A reappraisal of the checkerboard titration, often used in the optimisation of immunoassays, is discussed. Surprisingly, the highest sensitivity of the LFIA format (IC50 of 0.6 µg L¿1 progesterone in buffer) was achieved by using a high coating concentration of the analyte¿protein conjugate and a high dilution of the antibody solution. Immediate addition of all reagents in LFIA was superior to premixing the components and allowing prereaction. Of several blocking agents tested bovine serum albumin was superior in performance, whereas the combination of ovalbumin and progesterone substantially influenced test results.

Item does not contain fulltext, Reduced emotional expression has been consistently related to susceptibility or fast progression of breast cancer. Breast cancer development and reduced emotional expression have both been related to rejection- and separation-related conditions. The neuropeptide oxytocin is low in response to rejection or separation. Recent results suggest that oxytocin may protect against the development of breast cancer and slow its progression. In the present study, we investigated if individual differences in emotional expressivity relate to basal or cortisol-stimulated plasma oxytocin. Healthy female subjects were treated with placebo or 35 mg of cortisol orally in a double-blind within-subject study. Seventy minutes later, blood was sampled for determination of oxytocin and cortisol levels. We found an interaction between treatment condition and Emotional Expression-out scores: after cortisol treatment, oxytocin levels increased proportional to Emotion Expression-out score. These preliminary findings provide a potential mechanism for associations in the literature between emotional expressive behavior and breast cancer.

Item does not contain fulltext, Oxytocin and attachment seem to interact in suppressing subjective anxiety and physiological stress responses. In this study we investigated the relationships between individual differences in trait attachment scores, state and trait anxiety, plasma cortisol, and plasma oxytocin levels in healthy premenopausal women. Attachment proved to be a strong positive predictor of oxytocin levels, which were also positively predicted by cortisol levels and state and trait anxiety. The relationship between oxytocin and state anxiety was modulated by attachment scores. The present results may help interpreting seeming contradictions in the recent literature on oxytocin, attachment, and stress in humans, by suggesting that context effects determine which relationships are found in different studies: anxiolytic effects of oxytocin in a context of partner support versus stress- or cortisol-induced oxytocin responses in a context of distress or increased cortisol.

Item does not contain fulltext, Background. It has recently been proposed that major depression disorder (MDD) may, in a heterogeneous population-based cohort, be interpreted in terms of a random-mood model. Mood fluctuations are thought to result from stressors that occur randomly in time. We have investigated whether this concept also holds for more homogeneous groups, defined by known determinants for MDD, and whether the model's parameters., susceptibility (Z) and relaxation time (T), may be evaluated and used to differentiate between subcohorts. Method. From a large epidemiological survey, the Netherlands Mental Health Survey and Incidence Study (NEMESIS), data on the duration of MDD were obtained for subcohorts, based on gender, severity of depression, recurrence and co-morbidity with dysthymia, anxiety and somatic disorder, and were compared with random-mood Simulation calculations. Results. Susceptibility, Z, is empirically found to be proportional to incidence and may be identified with a risk ratio. A second scaling rule states the proportionality of mean duration with the product of Z and T. This Z-T classification proves to be more sensitive than conventional significance tests. Notably for men/women and for co-morbid anxiety, differences are seen that have previously gone unnoticed. Conclusions. Depression may be conceptualized as a disorder resulting from random-mood fluctuations, the response to which is influenced by a large variety of determinants or risk factors. The model's parameters can be evaluated and may be used in differentiating between risk factor-defined subLyroups.

Item does not contain fulltext, Oxytocin and attachment seem to interact in suppressing subjective anxiety and physiological stress responses. In this study we investigated the relationships between individual differences in trait attachment scores, state and trait anxiety, plasma cortisol, and plasma oxytocin levels in healthy premenopausal women. Attachment proved to be a strong positive predictor of oxytocin levels, which were also positively predicted by cortisol levels and state and trait anxiety. The relationship between oxytocin and state anxiety was modulated by attachment scores. The present results may help interpreting seeming contradictions in the recent literature on oxytocin, attachment, and stress in humans, by suggesting that context effects determine which relationships are found in different studies: anxiolytic effects of oxytocin in a context of partner support versus stress- or cortisol-induced oxytocin responses in a context of distress or increased cortisol.

Item does not contain fulltext, Reduced emotional expression has been consistently related to susceptibility or fast progression of breast cancer. Breast cancer development and reduced emotional expression have both been related to rejection- and separation-related conditions. The neuropeptide oxytocin is low in response to rejection or separation. Recent results suggest that oxytocin may protect against the development of breast cancer and slow its progression. In the present study, we investigated if individual differences in emotional expressivity relate to basal or cortisol-stimulated plasma oxytocin. Healthy female subjects were treated with placebo or 35 mg of cortisol orally in a double-blind within-subject study. Seventy minutes later, blood was sampled for determination of oxytocin and cortisol levels. We found an interaction between treatment condition and Emotional Expression-out scores: after cortisol treatment, oxytocin levels increased proportional to Emotion Expression-out score. These preliminary findings provide a potential mechanism for associations in the literature between emotional expressive behavior and breast cancer.

Item does not contain fulltext, Background. It has recently been proposed that major depression disorder (MDD) may, in a heterogeneous population-based cohort, be interpreted in terms of a random-mood model. Mood fluctuations are thought to result from stressors that occur randomly in time. We have investigated whether this concept also holds for more homogeneous groups, defined by known determinants for MDD, and whether the model's parameters., susceptibility (Z) and relaxation time (T), may be evaluated and used to differentiate between subcohorts. Method. From a large epidemiological survey, the Netherlands Mental Health Survey and Incidence Study (NEMESIS), data on the duration of MDD were obtained for subcohorts, based on gender, severity of depression, recurrence and co-morbidity with dysthymia, anxiety and somatic disorder, and were compared with random-mood Simulation calculations. Results. Susceptibility, Z, is empirically found to be proportional to incidence and may be identified with a risk ratio. A second scaling rule states the proportionality of mean duration with the product of Z and T. This Z-T classification proves to be more sensitive than conventional significance tests. Notably for men/women and for co-morbid anxiety, differences are seen that have previously gone unnoticed. Conclusions. Depression may be conceptualized as a disorder resulting from random-mood fluctuations, the response to which is influenced by a large variety of determinants or risk factors. The model's parameters can be evaluated and may be used in differentiating between risk factor-defined subLyroups.

Item does not contain fulltext, Oxytocin and attachment seem to interact in suppressing subjective anxiety and physiological stress responses. In this study we investigated the relationships between individual differences in trait attachment scores, state and trait anxiety, plasma cortisol, and plasma oxytocin levels in healthy premenopausal women. Attachment proved to be a strong positive predictor of oxytocin levels, which were also positively predicted by cortisol levels and state and trait anxiety. The relationship between oxytocin and state anxiety was modulated by attachment scores. The present results may help interpreting seeming contradictions in the recent literature on oxytocin, attachment, and stress in humans, by suggesting that context effects determine which relationships are found in different studies: anxiolytic effects of oxytocin in a context of partner support versus stress- or cortisol-induced oxytocin responses in a context of distress or increased cortisol.

Item does not contain fulltext, Reduced emotional expression has been consistently related to susceptibility or fast progression of breast cancer. Breast cancer development and reduced emotional expression have both been related to rejection- and separation-related conditions. The neuropeptide oxytocin is low in response to rejection or separation. Recent results suggest that oxytocin may protect against the development of breast cancer and slow its progression. In the present study, we investigated if individual differences in emotional expressivity relate to basal or cortisol-stimulated plasma oxytocin. Healthy female subjects were treated with placebo or 35 mg of cortisol orally in a double-blind within-subject study. Seventy minutes later, blood was sampled for determination of oxytocin and cortisol levels. We found an interaction between treatment condition and Emotional Expression-out scores: after cortisol treatment, oxytocin levels increased proportional to Emotion Expression-out score. These preliminary findings provide a potential mechanism for associations in the literature between emotional expressive behavior and breast cancer.

Item does not contain fulltext, Background. It has recently been proposed that major depression disorder (MDD) may, in a heterogeneous population-based cohort, be interpreted in terms of a random-mood model. Mood fluctuations are thought to result from stressors that occur randomly in time. We have investigated whether this concept also holds for more homogeneous groups, defined by known determinants for MDD, and whether the model's parameters., susceptibility (Z) and relaxation time (T), may be evaluated and used to differentiate between subcohorts. Method. From a large epidemiological survey, the Netherlands Mental Health Survey and Incidence Study (NEMESIS), data on the duration of MDD were obtained for subcohorts, based on gender, severity of depression, recurrence and co-morbidity with dysthymia, anxiety and somatic disorder, and were compared with random-mood Simulation calculations. Results. Susceptibility, Z, is empirically found to be proportional to incidence and may be identified with a risk ratio. A second scaling rule states the proportionality of mean duration with the product of Z and T. This Z-T classification proves to be more sensitive than conventional significance tests. Notably for men/women and for co-morbid anxiety, differences are seen that have previously gone unnoticed. Conclusions. Depression may be conceptualized as a disorder resulting from random-mood fluctuations, the response to which is influenced by a large variety of determinants or risk factors. The model's parameters can be evaluated and may be used in differentiating between risk factor-defined subLyroups.

This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver the reactants and the device was linked on-line to an electrochemical detector. The microreactor was used for on-line preparation of apoglucose oxidase in strong acid and its subsequent reactivation with flavin adenine dinucleotide. In addition we describe a miniaturized version of the microreactor used to assess several characteristics of femtomole to attomole amounts of glucose oxidase. A low negative potential over the electrodes was used when ferrocene was the mediator in combination with horseradish peroxidase, ensuring the absence of oxidation of electro-active compounds in biological fluids. A low backpressure at very low flow rates is an advantage, which increases the sensitivity. A variety of further applications of the microreactor are suggested.

Item does not contain fulltext, Treatment with cortisol has been found to decrease fatigue and increase feelings of vigor in both patients and healthy male subjects. We obtained self-reports of mood before 35 mg cortisol or placebo ingestion, 70 min later, and after the healthy female subjects performed cognitive tasks for 1 h in a double-blind within-subject study. Cortisol decreased fatigue, increased vigor, and tended to decrease tension. Effects on fatigue were largest after task performance, when fatigue had increased, suggesting that improvement of fatigue by cortisol is observed when subjects are fatigued. This is the first study to demonstrate improvements in fatigue in healthy female subjects; this is particularly relevant because of the high prevalence of hypocortisolimic fatigue syndromes in women and recent evidence that many psychiatric disorders may involve stress-induced hypocortisolemia that is responsive to cortisol replacement.

Item does not contain fulltext, In the present study we investigated the effects of cortisol administration on EEG activity in eight healthy volunteers. We administered 35 mg of cortisol in a within-subjects double-blind placebo-controlled design. Cortisol administration caused a global decrease in cortical activity except for an increase frontally at the left, resulting in a significant change in frontal asymmetry. This pattern of results is almost the exact mirror image of one of our previous studies. Comparing subjective activation measures from the present and previous study showed that activation was substantially higher in the present study that was performed in formal testing conditions involving venipuncture, compared to the previous EEG study that was performed in non-formal testing conditions. However, the direction of the present cortisolinduced change in frontal activity asymmetry is consistent with the cortisolinduced change in asymmetric rotation behavior that we recently reported in similar testing conditions. We also found indications that, in contrast to the effects on the EEG measures, effects of cortisol administration on subjective anxiety and plasma oxytocin levels may be sex-dependent. These results are preliminary because of the post-hoc nature and the small number of subjects in the present study. However, they are in line with recent findings by others, suggesting that the effects of cortisol on cortical activity and subjective activation are state dependent and are influenced by testing conditions.

Contains fulltext : 126902.pdf (publisher's version ) (Open Access), Context: Mathematical models describing changes in mood in affective disorders may assist in the identification of underlying pathologic and neurobiologic mechanisms and in differentiating between alternative interpretations of psychiatric data. Objective: Using time-to-event data from a large epidemiologic survey on recovery from major depression, to model the survival probability, in terms of an underlying process, with parameters which might be recognized and influenced in clinical practice. Design: We present a sequential-phase model for survival analysis, which describes depression as a state with or without an additional incubation phase. Recovery is seen as the transition to a nondepressive state. We show that this sequential-phase model finds a microscopic realization in a dynamic description, the random-mood model, which depicts mood as governed by an Ornstein-Uhlenbeck type of stochastic process, driven by intermittent gaussian noise. Results: For reversible depression (80%), the fractional probability of recovery is remarkably independent of the history of the depression. Analysis with the sequential-phase model suggests single exponential decay in this group, possibly with a short incubation phase. Within the random-mood model, the data for this reversibly depressed cohort are compatible with an intermittent noise pattern of stimuli with average spacing of 4 months and incompatible with nonintermittent noise. Conclusions: Time-to-event data from psychiatric epidemiologic studies can be conceptualized through modeling as intrasubject processes. The proposed random-mood model reproduces the time-to-event data and explains the incubation phase as an artifact due to the inclusion criterion of 14 days in most current psychiatric diagnostic systems. Depression is found to result more often from pileup of negative stimuli than from single life events. Time sequences, generated using the random-mood model, produce power plots, phase-space trajectories, and pair

Item does not contain fulltext, In the present study we investigated the effects of cortisol administration on EEG activity in eight healthy volunteers. We administered 35 mg of cortisol in a within-subjects double-blind placebo-controlled design. Cortisol administration caused a global decrease in cortical activity except for an increase frontally at the left, resulting in a significant change in frontal asymmetry. This pattern of results is almost the exact mirror image of one of our previous studies. Comparing subjective activation measures from the present and previous study showed that activation was substantially higher in the present study that was performed in formal testing conditions involving venipuncture, compared to the previous EEG study that was performed in non-formal testing conditions. However, the direction of the present cortisolinduced change in frontal activity asymmetry is consistent with the cortisolinduced change in asymmetric rotation behavior that we recently reported in similar testing conditions. We also found indications that, in contrast to the effects on the EEG measures, effects of cortisol administration on subjective anxiety and plasma oxytocin levels may be sex-dependent. These results are preliminary because of the post-hoc nature and the small number of subjects in the present study. However, they are in line with recent findings by others, suggesting that the effects of cortisol on cortical activity and subjective activation are state dependent and are influenced by testing conditions.

Contains fulltext : 126902.pdf (publisher's version ) (Open Access), Context: Mathematical models describing changes in mood in affective disorders may assist in the identification of underlying pathologic and neurobiologic mechanisms and in differentiating between alternative interpretations of psychiatric data. Objective: Using time-to-event data from a large epidemiologic survey on recovery from major depression, to model the survival probability, in terms of an underlying process, with parameters which might be recognized and influenced in clinical practice. Design: We present a sequential-phase model for survival analysis, which describes depression as a state with or without an additional incubation phase. Recovery is seen as the transition to a nondepressive state. We show that this sequential-phase model finds a microscopic realization in a dynamic description, the random-mood model, which depicts mood as governed by an Ornstein-Uhlenbeck type of stochastic process, driven by intermittent gaussian noise. Results: For reversible depression (80%), the fractional probability of recovery is remarkably independent of the history of the depression. Analysis with the sequential-phase model suggests single exponential decay in this group, possibly with a short incubation phase. Within the random-mood model, the data for this reversibly depressed cohort are compatible with an intermittent noise pattern of stimuli with average spacing of 4 months and incompatible with nonintermittent noise. Conclusions: Time-to-event data from psychiatric epidemiologic studies can be conceptualized through modeling as intrasubject processes. The proposed random-mood model reproduces the time-to-event data and explains the incubation phase as an artifact due to the inclusion criterion of 14 days in most current psychiatric diagnostic systems. Depression is found to result more often from pileup of negative stimuli than from single life events. Time sequences, generated using the random-mood model, produce power plots, phase-space trajectories, and pair

Item does not contain fulltext, Treatment with cortisol has been found to decrease fatigue and increase feelings of vigor in both patients and healthy male subjects. We obtained self-reports of mood before 35 mg cortisol or placebo ingestion, 70 min later, and after the healthy female subjects performed cognitive tasks for 1 h in a double-blind within-subject study. Cortisol decreased fatigue, increased vigor, and tended to decrease tension. Effects on fatigue were largest after task performance, when fatigue had increased, suggesting that improvement of fatigue by cortisol is observed when subjects are fatigued. This is the first study to demonstrate improvements in fatigue in healthy female subjects; this is particularly relevant because of the high prevalence of hypocortisolimic fatigue syndromes in women and recent evidence that many psychiatric disorders may involve stress-induced hypocortisolemia that is responsive to cortisol replacement.

Item does not contain fulltext, In the present study we investigated the effects of cortisol administration on EEG activity in eight healthy volunteers. We administered 35 mg of cortisol in a within-subjects double-blind placebo-controlled design. Cortisol administration caused a global decrease in cortical activity except for an increase frontally at the left, resulting in a significant change in frontal asymmetry. This pattern of results is almost the exact mirror image of one of our previous studies. Comparing subjective activation measures from the present and previous study showed that activation was substantially higher in the present study that was performed in formal testing conditions involving venipuncture, compared to the previous EEG study that was performed in non-formal testing conditions. However, the direction of the present cortisolinduced change in frontal activity asymmetry is consistent with the cortisolinduced change in asymmetric rotation behavior that we recently reported in similar testing conditions. We also found indications that, in contrast to the effects on the EEG measures, effects of cortisol administration on subjective anxiety and plasma oxytocin levels may be sex-dependent. These results are preliminary because of the post-hoc nature and the small number of subjects in the present study. However, they are in line with recent findings by others, suggesting that the effects of cortisol on cortical activity and subjective activation are state dependent and are influenced by testing conditions.

Contains fulltext : 126902.pdf (publisher's version ) (Open Access), Context: Mathematical models describing changes in mood in affective disorders may assist in the identification of underlying pathologic and neurobiologic mechanisms and in differentiating between alternative interpretations of psychiatric data. Objective: Using time-to-event data from a large epidemiologic survey on recovery from major depression, to model the survival probability, in terms of an underlying process, with parameters which might be recognized and influenced in clinical practice. Design: We present a sequential-phase model for survival analysis, which describes depression as a state with or without an additional incubation phase. Recovery is seen as the transition to a nondepressive state. We show that this sequential-phase model finds a microscopic realization in a dynamic description, the random-mood model, which depicts mood as governed by an Ornstein-Uhlenbeck type of stochastic process, driven by intermittent gaussian noise. Results: For reversible depression (80%), the fractional probability of recovery is remarkably independent of the history of the depression. Analysis with the sequential-phase model suggests single exponential decay in this group, possibly with a short incubation phase. Within the random-mood model, the data for this reversibly depressed cohort are compatible with an intermittent noise pattern of stimuli with average spacing of 4 months and incompatible with nonintermittent noise. Conclusions: Time-to-event data from psychiatric epidemiologic studies can be conceptualized through modeling as intrasubject processes. The proposed random-mood model reproduces the time-to-event data and explains the incubation phase as an artifact due to the inclusion criterion of 14 days in most current psychiatric diagnostic systems. Depression is found to result more often from pileup of negative stimuli than from single life events. Time sequences, generated using the random-mood model, produce power plots, phase-space trajectories, and pair

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A simple portable continuous L-lactate monitoring system combining elegant ultrafiltration sample collection and storage with a lactate biosensor has been developed. The sensor has a detection range from 0.05mM to 30mM lactate dependent on different assignments of the PCS hydrogel complex layer. The sensor shows excellent performance on sensitivity and validity as well as operational stability over one month. Samples containing different concentrations of lactate were collected in six hours with an ultrafiltration probe and stored in a 6m long PEEK tube of 125 mu m in internal diameter. The ultraslow flow rate of 100 to 350nl/min was controlled by adjusting the restriction in the portable plastic syringe pump and a constant flow can be maintained over 24 hours. The collected samples were then detected after reversing the now with a lactate sensor. The total weight of the collection system is only 8g, allowing free movement of the person being tested.

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A simple portable continuous L-lactate monitoring system combining elegant ultrafiltration sample collection and storage with a lactate biosensor has been developed. The sensor has a detection range from 0.05mM to 30mM lactate dependent on different assignments of the PCS hydrogel complex layer. The sensor shows excellent performance on sensitivity and validity as well as operational stability over one month. Samples containing different concentrations of lactate were collected in six hours with an ultrafiltration probe and stored in a 6m long PEEK tube of 125 mu m in internal diameter. The ultraslow flow rate of 100 to 350nl/min was controlled by adjusting the restriction in the portable plastic syringe pump and a constant flow can be maintained over 24 hours. The collected samples were then detected after reversing the now with a lactate sensor. The total weight of the collection system is only 8g, allowing free movement of the person being tested.

Item does not contain fulltext, Mounting evidence suggests involvement of prenatal factors in the pathogenesis of schizophrenia. The objective of the present study was to provide evidence for the hypothesis on schizophrenia that abnormal fetal brain development leads to impaired sensorimotor gating of acoustic startle stimuli. To this purpose, pregnant rats were treated with methylazoxymethanol acetate on one of four subsequent days of gestation, from E9 to E12. These procedures inhibit early stages of cortical proliferation in the foetuses, resulting in early abnormalities that were mainly found in the entorhinal region. At the adult age, habituation and prepulse inhibition (PPI) of startle responses to acoustic stimuli were investigated. Our results show impaired habituation and PPI in rats treated at embryonic days 10 and 11. It is concluded that sensorimotor gating deficits can result from a developmental abnormality involving the entorhinal region, supporting the hypothesis that similar deficits, often observed in schizophrenic subjects may be the result of entorhinal cortex dysfunction.

Item does not contain fulltext, Mounting evidence suggests involvement of prenatal factors in the pathogenesis of schizophrenia. The objective of the present study was to provide evidence for the hypothesis on schizophrenia that abnormal fetal brain development leads to impaired sensorimotor gating of acoustic startle stimuli. To this purpose, pregnant rats were treated with methylazoxymethanol acetate on one of four subsequent days of gestation, from E9 to E12. These procedures inhibit early stages of cortical proliferation in the foetuses, resulting in early abnormalities that were mainly found in the entorhinal region. At the adult age, habituation and prepulse inhibition (PPI) of startle responses to acoustic stimuli were investigated. Our results show impaired habituation and PPI in rats treated at embryonic days 10 and 11. It is concluded that sensorimotor gating deficits can result from a developmental abnormality involving the entorhinal region, supporting the hypothesis that similar deficits, often observed in schizophrenic subjects may be the result of entorhinal cortex dysfunction.

In standard displacement flow immunoassays the analyte in the sample creates an active dissociation of labelled antigens (or antigen homologues) from an antigen binding site of an immobilized antibody, after which the labelled substance is measured downstream. Such systems have been described for molecules up to 1 kDa, In this study, we demonstrate displacement in a flow system for the detection of a small protein, cytoplasmic heart-type fatty acid-binding protein (15 kDa), a plasma marker for myocardial injury. The displacement system uses an inverse set-up: enzyme labelled monoclonal antibodies are associated to immobilized antigen, and are displaced by analyte in the sample. The system permits detection of both physiological (2-12 mu g l(-1)) and pathological concentrations (12-2000 mu g l(-1)) of fatty acid-binding protein in an on-line flow system. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

In standard displacement flow immunoassays the analyte in the sample creates an active dissociation of labelled antigens (or antigen homologues) from an antigen binding site of an immobilized antibody, after which the labelled substance is measured downstream. Such systems have been described for molecules up to 1 kDa, In this study, we demonstrate displacement in a flow system for the detection of a small protein, cytoplasmic heart-type fatty acid-binding protein (15 kDa), a plasma marker for myocardial injury. The displacement system uses an inverse set-up: enzyme labelled monoclonal antibodies are associated to immobilized antigen, and are displaced by analyte in the sample. The system permits detection of both physiological (2-12 mu g l(-1)) and pathological concentrations (12-2000 mu g l(-1)) of fatty acid-binding protein in an on-line flow system. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

In standard displacement flow immunoassays the analyte in the sample creates an active dissociation of labelled antigens (or antigen homologues) from an antigen binding site of an immobilized antibody, after which the labelled substance is measured downstream. Such systems have been described for molecules up to 1 kDa, In this study, we demonstrate displacement in a flow system for the detection of a small protein, cytoplasmic heart-type fatty acid-binding protein (15 kDa), a plasma marker for myocardial injury. The displacement system uses an inverse set-up: enzyme labelled monoclonal antibodies are associated to immobilized antigen, and are displaced by analyte in the sample. The system permits detection of both physiological (2-12 mu g l(-1)) and pathological concentrations (12-2000 mu g l(-1)) of fatty acid-binding protein in an on-line flow system. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

Contains fulltext : 22706___.PDF (publisher's version ) (Open Access)

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Contains fulltext : 22706___.PDF (publisher's version ) (Open Access)

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Contains fulltext : 22706___.PDF (publisher's version ) (Open Access)

Item does not contain fulltext