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Biomedical subjects

L de Haan

Publications and source records attributed to L de Haan.

At least 19 recordsLinked to original sources
PubMed2005

[The optimal level of dopaminergic neurotransmission].

Dopaminergic neurotransmission affects an individual's subjective experience. Individuals with lower baseline dopamine function are at an increased risk for dysphoric responses during antipsychotic therapy with dopaminergic-blocking drugs. Reaching an optimal dopamine D2-receptor occupancy is therefore relevant for the quality of life. Doses of antipsychotic drugs administered to such individuals often need to be lower than the commonly used levels, as these may induce drowsiness and lack of energy.

Antipsychotic Agents↗
PubMed2005

Comparison of clinical and pathological diagnoses in dogs.

Clinical and pathological diagnoses were compared in a prospective study of 145 dogs. A diagnostic work up had been performed on all dogs of which 36 (24.8%) died and 109 (75.2%) were euthanatized. In 119 dogs (82.1%) both a clinical and patholical diagnosis was made, in 20 dogs (13.8%) no pathological diagnosis could be made and in 6 dogs (4.1%) no clinical diagnosis was established. In the 119 dogs the agreement level between clinical and pathological diagnosis was scored by the referring veterinarian together with a pathologist. Total agreement was found in 61 cases (51.3%) and disagreement in 31 cases (26.0%). In the remaining cases (27=22.7%) the pathological diagnosis further specified the clinical diagnosis. Consecutive submission appeared difficult to achieve by the participating veterinarians. However, no major differences in agreement level was present between the veterinarian which succeeded in almost consecutive submissions and the other veterinarians. At necropsy 42 cases were diagnosed as neoplasia, of which 52.4% had been diagnosed clinically. As to infectious diseases 55.0% of these diseases diagnosed at necropsy had been diagnosed clinically. In about 20% of the cases the differences were of clinical significance according to the referring veterinarians. In addition, it was indicated by the clinicians that about 50% of the necropsies revealed findings which could amend future patient care. The results of the study stress the relevance of postmortem examination as crucial part of continuing education and of quality monitoring and assurance in veterinary medicine.

Animals↗
PubMed2005

Adolescence, schizophrenia and drug abuse: a window of vulnerability.

OBJECTIVE: To discuss the neurobiological and psychosocial developmental factors in adolescence contributing to simultaneous onset and co-occurrence of psychosis and substance use disorders. METHOD: A review of the literature. RESULTS: Adolescence is a period with specific psychosocial challenges and specific changes in the brain that increase the probability of the onset of both psychosis and substance abuse, in predisposed people. In vulnerable adolescents it is proposed that an excessive pruning of dopaminergic neurones leads to mesocortical hypofrontality causing anhedonia and dysphoria. At the same time, anhedonia and dysphoria are important risk factors for the development of substance abuse. In turn, hypofrontality leads to a reduction in mesocortical feedback inhibition of the mesolimbic system resulting in aberrant salience and positive symptoms. Finally, the development of aberrant salience plays a role in both psychoses and craving. CONCLUSION: Attention should be paid to the interaction of drug abuse and schizophrenia and an integrated treatment is needed. Dysphoria and anhedonia in schizophrenic adolescents are important factors in treatment with antipsychotic medication, both in terms of patient satisfaction and in the prevention of substance abuse.

Adolescent↗
PubMed2004

Overview of neuropathological theories of schizophrenia: from degeneration to progressive developmental disorder.

Based on a review of literature three main hypotheses on the neuropathology of schizophrenia are identified: (1). neurodegeneration, (2). a disorder that is limited to the early development of the brain, and (3). a progressive developmental disorder. Research findings and clinical observations present evidence that the neurodegeneration hypothesis can be considered inaccurate; they also present several arguments against a disorder that is confined to early development. They are compatible, however, with a progressive developmental disorder. The hypothesis that schizophrenia is a disorder of developmentally reduced synaptic connectivity can account for important aspects of schizophrenia and gives an argument for further research into the possibilities and results of early treatment and perhaps even treatment prior to the first psychotic episode.

Adult↗
PubMed2004

Opinions of mothers on the first psychotic episode and the start of treatment of their child.

Parents, especially mothers, have a critical role in initiating psychiatric treatment for their child with first-episode schizophrenia. Knowledge of attitudes of mothers towards the illness of their child prior to psychiatric treatment and towards the start of treatment is essential for the development of interventions for reducing duration of untreated psychosis (DUP). In the present study, mothers (n = 61) of consecutively admitted patients with recent-onset schizophrenic disorders were interviewed about: their views on the nature of the symptoms at first occurrence of psychotic symptoms in their child and views on the main reason for psychiatric treatment; their perception of problems in initiating psychiatric treatment; and suggestions they might have for getting treatment started at an earlier point in time. About 57% of the mothers did not think that their child had a psychosis at first occurrence of psychotic symptoms. Most of the mothers who immediately thought that their child suffered from a psychotic disorder supposed that this disorder was caused by use of street drugs. About one-third (32.8%) of the mothers thought that the reluctance of patients to acknowledge that they needed help was the major obstacle in initiating psychiatric treatment. More than half of the mothers perceived factors related to the delivery of professional care as problems in initiating psychiatric treatment. Given the reluctance of patients to accept treatment, these problems further complicate the initiating of treatment. Mothers emphasize that a more active approach by professional caregivers could reduce treatment delay.

Adult↗
PubMed2002

[Schizophrenia and the 22q11 deletion syndrome].

In 10-30% of the patients with the 22q11 deletion syndrome (22q11DS), a psychosis develops in adulthood, often schizophrenia. 22q11DS is a common genetic syndrome which is associated with an interstitial deletion at chromosome 22q11. The syndrome is characterised by a variable phenotype which includes cognitive and behavioural problems, in addition to congenital heart and facial anomalies. The presence of 22q11DS represents one of the highest risk factors for the development of schizophrenia. The study of 22q11DS offers a unique opportunity to increase the understanding of the pathogenesis of schizophrenia.

Chromosomes, Human, Pair 22↗
PubMed2002

Psychometric properties of the Subjective Well-Being Under Neuroleptics scale and the Subjective Deficit Syndrome Scale.

RATIONALE: Subjective experience of antipsychotic drugs is relevant for medication compliance and quality of life. There is, however, sparse knowledge about the assessment of subjective experience. OBJECTIVES: To examine the internal consistency, test-retest reliability, sensitivity to medication change and concurrent validity of two test instruments: the Subjective Well-Being Under Neuroleptics (SWN) and the Subjective Deficit Syndrome Scale (SDSS). METHODS: Both instruments were used at admission and after 6 weeks of medication stabilization in 105 consecutively admitted patients diagnosed with DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edn) diagnoses of recent-onset schizophrenia, schizophreniform disorder or schizoaffective disorder. RESULTS: Almost all patients were capable of reproducing their subjective experience in a consistent way both before and after medication stabilization. The internal consistency of both instruments was high. The test-retest reliability was high if medication was not changed, especially for the SWN. The SWN was sensitive for changes in medication and dosage. The short form of the SWN (SWN-20 items) had comparable psychometric qualities to the original instrument (SWN-38 items). The concurrent validity of the SWN and the SDSS was good, indicating that both tests measure the same concept. CONCLUSIONS: The assessment of subjective experience with the SWN (both versions) may be used in evaluating differential effects of anti-psychotics and dose on subjective well-being.

Adolescent↗
PubMed2002

Priorities and satisfaction on the help needed and provided in a first episode of psychosis. A survey in five European Family Associations.

In the case of a first episode of psychosis among members of different associations of families of mentally ill people, little is known about their priorities and how satisfied they are with the help provided to them. A survey was conducted in five European family associations. Respondents emphasized the need for early (ambulant) intervention through outreach with very practical goals directed at creating stability and social functioning. About one-third of the respondents are unsatisfied or very unsatisfied. The highest percentage of unsatisfied respondents was in the following five areas of care: advice on how to handle specific problems; help with preserving or regaining social functioning; help with regaining structure and routine; information; prompt assistance preferably in patients own environment. The agreement of these findings with findings from earlier studies underlines the importance of suggesting specific changes in the delivery of care.

Adult↗
PubMed2001

Preferences for treatment during a first psychotic episode.

Psychiatric services providing care for patients and their families confronted with a first psychotic episode need to be sensitive towards patients' and families' preferences. Ten patients, ten family members and ten professional caregivers composed a list of 42 preferences in the treatment for a first psychotic episode. In total 99 patients, 100 family members and 263 professional caregivers evaluated these preferences, thus producing an order of priorities. There appears to be considerable agreement among the groups of respondents regarding their top ten priorities, especially concerning information on diagnosis and medication. However, we found important differences between groups of respondents. The results suggest that in psychiatric services great attention should be given to psycho-education and early outpatient intervention.

Adult↗
PubMed2001

Estrogenic activity of estradiol and its metabolites in the ER-CALUX assay with human T47D breast cells.

A number of metabolites of 17beta-estradiol were tested for their estrogenic activity using the ER-CA-LUX assay based on the increased expression of luciferase in exposed T47D breast cancer cells. E2beta and estrone showed similar potencies in the test, whereas E2alpha was 100 times less active. Incubation of cells with estrone (0.35 microM) resulted in the formation of E2beta, whereas the reverse reaction was observed for E2beta. The resulting equilibrium may explain the similar estrogenic potency of estrone in the test. The synthetic 17-hydroxy benzoate ester of E2beta was 3 times less active than the parent compound. The 17-hydroxy palmitate and oleate esters of E2beta, were respectively 25 and 200 times less active than the parent compound. The 2-hydroxy metabolites of E2beta and estrone showed a 5,000 to 10,000 fold lower activity. The 4-hydroxy metabolites were more potent than the 2-hydroxy metabolites, showing only a 20-200 times lower activity. The 2- and 4-methoxyesters of estrone were 700 times less active. It is concluded that the estrogenic potency of metabolites formed in cattle after treatment with E2beta, like estrone, E2alpha and especially the esters of E2beta, may be significant with respect to the potential risk of the use of estradiol for growth promotion in domestic animals in certain countries.

Estradiol↗
PubMed2001

Social functioning and the course of early-onset schizophrenia: five-year follow-up of a psychosocial intervention.

BACKGROUND: Schizophrenia implies severe social impairments. Since the treatment of patients with schizophrenia shifted from long-term hospital admissions to community services, research on social functioning has become increasingly important. AIMS: Follow-up assessment of social functioning in young patients with schizophrenia during a 5-year period after intervention. METHOD: During intervention, families were randomised into two conditions: standard intervention and standard plus family intervention. RESULTS: Although no differential treatment effect with regard to the course of the illness was found, patients from the standard plus family intervention condition stayed for fewer months in institutions for psychiatric patients than patients from the standard intervention condition. CONCLUSIONS: Family intervention has helped parents to support their children, thereby diminishing institutional care.

Activities of Daily Living↗
PubMed2000

Duration of untreated psychosis and the long-term course of schizophrenia.

This study examines the relationship between duration of untreated psychosis (DUP) and long-term symptomatic and social outcome in 205 patients with schizophrenia, whose parents are member of a consumer organisation. We found only a tendency that longer DUP was related to negative symptoms, but no relation to other outcome domains. The results of this study do not support antipsychotic intervention at the earliest sign of psychosis in order to 'protect the brain'.

Adult↗
PubMed2000

Subjective experience and striatal dopamine D(2) receptor occupancy in patients with schizophrenia stabilized by olanzapine or risperidone.

OBJECTIVE: The authors' goal was to study the relationship between subjective experience during treatment with olanzapine or risperidone and dopamine D(2) receptor occupancy in stabilized patients with schizophrenia. METHOD: Subjective experience, psychopathology, and extrapyramidal symptoms were assessed, and D(2) receptor occupancy was determined with [(123)I]iodobenzamide single photon emission computed tomography, in 22 patients whose schizophrenia was stabilized by olanzapine or risperidone. RESULTS: Subjective experience, depression, and negative symptoms were related to dopamine D(2) receptor occupancy, but extrapyramidal symptoms were not. CONCLUSIONS: These results provide preliminary evidence that negative subjective experience is related to high D(2) receptor occupancy. Longitudinal study is required because this relationship may have implications for dosing strategies.

Adolescent↗
PubMed2000

Cholera toxin and related enterotoxins: a cell biological and immunological perspective.

Cholera toxin (Ctx) from Vibrio cholerae and the closely related Escherichia coli heat-labile enterotoxin (Etx) are the primary virulence factors responsible for causing cholera and traveller's diarrhea, respectively. Studies on the mode of action of these toxins on gut epithelial cells have revealed important insights into the mechanisms of toxin uptake and trafficking in eukaryotic cells. However, of perhaps even greater fascination have been the discoveries that Ctx and Etx exhibit remarkable immunological properties. When either of these toxins is administered via mucosal routes, it triggers a potent mucosal and systemic anti-toxin immune response. By contrast, local or systemic immunization with other soluble protein antigens usually stimulates only a meagre immune response, or results in a state of immunological tolerance. Even more striking are the findings that when Ctx or Etx are mixed with heterologous antigens, they function as adjuvants, leading to stimulation of mucosal responses to the admixed antigen, and the abrogation of oral tolerance. In addition, recent observations have shown that the receptor-binding component of these toxins can down-regulate inflammatory diseases associated with the induction of autoimmune disorders such as rheumatoid arthritis, diabetes, and multiple sclerosis. While the underlying mechanisms responsible for these remarkable properties have yet to be resolved, it is clear that the toxins' ability to bind to cell surface receptors plays an important role in their potent immunogenicity, adjuvanticity, and immunotherapeutic properties. This review provides an overview of the latest developments within the Ctx/Etx field, with a special emphasis on the cell entry mechanisms and immunomodulatory action of Ctx/Etx and their component subunits.

Antibody Formation↗
PubMed1999

Clozapine and obsessions in patients with recent-onset schizophrenia and other psychotic disorders.

BACKGROUND: The increase or emergence of obsessions was compared in young patients with recent-onset schizophrenia or other psychotic disorders taking clozapine and other antipsychotic drugs. METHOD: We conducted a retrospective cohort study. Subjects were 121 consecutively admitted patients diagnosed with DSM-III-R schizophrenia, schizoaffective disorder, schizophreniform disorder, or psychotic disorder not otherwise specified. Obsessions were diagnosed according to DSM-IV criteria. RESULTS: More clozapine-treated subjects (20.6%) than subjects treated with other antipsychotic drugs (1.3%) experienced an emergence or increase of obsessions (p<.01). CONCLUSION: Use of clozapine is associated with the emergence or increase of obsessions in early-phase schizophrenia.

Adult↗