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G Parker

Publications and source records attributed to G Parker.

At least 73 records · Page 4Linked to original sources
PubMed2001

Schizophrenia today: what do we know-and how sure are we?

The growth of our understanding of the biology and treatment of schizophrenia is still very much a work in progress. In this article, which introduces a series of papers presented at a conference entitled "Schizophrenia: Doing the Right Thing Well," held at Northcoast Behavioral Healthcare System (Cleveland, May 2000), the authors provide a short overview of what is known about schizophrenia today. He briefly reviews findings concerning epidemiology, phenomenology and course, neurobiology, and treatment, and highlights some of the most significant findings to date as well as areas needing further research. Early evaluation and treatment, in advance of the florid presentation of the illness, offer much hope, but only if our knowledge of the diagnostic specificity of prodromal and neurodevelopmental precursors can be enhanced. Significant advances in medication treatment have been made, and the newer antipsychotic medications overall have a more benign adverse-effect profile than the older agents, although the specter of endocrine/metabolic complications looms as a significant long-term concern. The authors conclude that, although many advances in our understanding of the etiology and treatment of schizophrenia have been made, much remains to be learned.

Journal Article↗
PubMed2001

Evidence for redundancy in cysteine biosynthesis in Rhizobium leguminosarum RL3841: analysis of a cysE gene encoding serine acetyltransferase.

A cysE gene encoding a serine acetyltransferase (SAT) potentially involved in the biosynthesis of cysteine was identified approximately 4 kb upstream of the previously described aapJQMP gene cluster that encodes an amino acid permease in Rhizobium leguminosarum strain 3841. The gene exhibits >40% identity to the family of SATs containing N-terminal extensions that have been described for other bacteria and plants. The ORF has three possible translation initiation sites which potentially encode polypeptides of 311, 277 and/or 259 amino acid residues, respectively. All three ORFs complemented the cysE mutation in an Escherichia coli cysteine auxotroph, strain JM39. Insertion of Tn5-lacZ into cysE in the genome of R. leguminosarum (strain RU632) lowered SAT activity in crude extracts by >95%. However, RU632 was not a cysteine auxotroph, which suggests that R. leguminosarum possesses some redundancy in cysteine biosynthesis. Additional copies of cysE could not be detected in the genome when the R. leguminosarum cysE gene was used as a hybridization probe. Therefore it is possible that R. leguminosarum possesses an alternative pathway for cysteine biosynthesis which avoids O-acetylserine. Strain RU632 was unaffected in its ability to nodulate Pisum sativum, and the nodules were effective for N(2) fixation (measured by C(2)H(2) reduction). Transcriptional activity of cysE was determined by measuring the beta-galactosidase arising from cysE::Tn5-lacZ fusions. Maximal levels of expression were observed during early exponential growth and were not influenced by the level of sulphur (supplied as sulphate). However, transcription was repressed by approximately twofold in ammonium-grown, as opposed to glutamate-grown, cultures. Repression by ammonium was not seen in a strain defective for ntrC.

Acetyltransferases↗
PubMed2001

Physical and functional interactions between the corepressor CtBP and the Epstein-Barr virus nuclear antigen EBNA3C.

CtBP has been shown to be a highly conserved corepressor of transcription. E1A and all the various transcription factors to which CtBP binds contain a conserved PLDLS CtBP-interacting domain, and EBNA3C includes a PLDLS motif (amino acids [aa] 728 to 732). Here we show that EBNA3C binds to CtBP both in vitro and in vivo and that the interaction requires an intact PLDLS. The C terminus of EBNA3C (aa 580 to 992) has modest trans-repressor activity when it is fused to the DNA-binding domain of Gal4, and deletion or mutation of the PLDLS sequence ablates this and unmasks a transactivation function within the fragment. However, loss of the CtBP interaction motif had little effect on the ability of full-length EBNA3C to repress transcription. A striking correlation between CtBP binding and the capacity of EBNA3C to cooperate with (Ha-)Ras in the immortalization and transformation of primary rat embryo fibroblasts was also revealed.

Alcohol Oxidoreductases↗
PubMed2001

Development of guidelines to facilitate improved support of South Asian carers by primary health care teams.

BACKGROUND: Evidence based guidelines are regarded as an appropriate basis for providing effective health care, but few guidelines incorporate the views of users such as carers. AIM: To develop guidelines to assist primary health care teams (PHCTs) in their work with carers within South Asian communities. METHODS: The guidelines were drawn up by a development group consisting of members of teams in areas with South Asian communities (Leicester and Bradford). The teams were invited to make their recommendations based on a systematic review of literature on minority ethnic carers and the findings of a study of the needs and experiences of local South Asian carers. A grading system was devised to enable the teams and a group of expert peer reviewers to assess the quality of evidence in support of each recommendation. RESULTS: The teams agreed seven recommendations, graded according to available evidence and strength of opinion. External peer review supported the PHCTs' interpretation of evidence and their recommendations. The recommendations included consideration of communication and information for carers, coordination of care within teams, and recognition by team members of the roles of carers and their cultural and religious beliefs. CONCLUSION: There are particular steps that PHCTs can take to improve their support of South Asian carers. It is possible to develop guidelines that take users' views into account and incorporate evidence from qualitative studies.

Asia, Western↗
PubMed2001

Depression in the planet's largest ethnic group: the Chinese.

OBJECTIVE: The authors reviewed the evidence for the claim that the Chinese tend to deny depression or express it somatically, examined the possible determinants of those characteristics, and explored implications of the findings for the diagnosis and management of depression in China and for psychiatry in the WEST: METHOD: This paper reviews and interprets original studies and literature reviews considering emotional distress, depression, neurasthenia, and somatization in Chinese subjects. RESULTS: Interpretation of the literature is complicated by the considerable heterogeneity among people described as "the Chinese" and by numerous factors affecting collection of data, including issues of illness definition, sampling, and case finding; differences in help-seeking behavior; idiomatic expression of emotional distress; and the stigma of mental illness. Despite difficulties in interpreting the literature, the available data suggest that the Chinese do tend to deny depression or express it somatically. CONCLUSIONS: The existing evidence supports the hypothesis that the Chinese tend to deny depression or express it somatically. However, Western influences on Chinese society and on the detection and identification of depression are likely to have modified the expression of depressive illness quite sharply since the early 1980s. Analyzing these changes may provide useful insight into the evolution of the diagnosis of depression in Western and other cultures.

Acculturation↗
PubMed2001

A question of style: refining the dimensions of personality disorder style.

The frequent finding that meeting criteria for one type of personality disorder (PD) is commonly associated with meeting criteria for several other PDs indicates significant problems in defining and measuring PDs independently of each other, whether measured categorically or dimensionally. This study was designed to enrich recent DSM descriptor sets and, with the enriched set of descriptors, develop refined PD dimensions. A large sample of patients with a PD or significant personality disturbance were studied, with most analyses based on self-report (SR) data, but with corroborative witness (CW) data also collected to validate refinement analyses. The original descriptor set comprised 139 DSM descriptors and 127 items obtained from other sources. Personality disorder dimensions of interest were refined by factor analyses. We specifically identify items that failed to "belong" to their original PD "base." A refined set of 92 items demonstrated greater independence of the underlying dimensions and suggested an underlying five-factor structure at some variance to the current DSM-IV cluster set. The study should assist measurement of individual PDs by identifying items and constructs that build to more homogeneous dimensions that define lower-order and higher-order PD traits.

Adult↗
PubMed2001

Endovascular treatment of cranial venous sinus obstruction resulting in pseudotumor syndrome. Report of three cases.

It is probable that a significant number of cases of pseudotumor syndrome (PTS) occur because of cranial venous outflow obstruction, yet reports of direct treatment of the obstruction are few and inconclusive. In this study the authors report three cases of PTS with angiographically confirmed venous sinus obstruction treated by direct, endovascular procedures; urokinase infusion in two and balloon venoplasty in one. Two patients suffered transient complications that resolved satisfactorily. All three showed initial resolution of the signs and symptoms of PTS but one relapsed after 8 months and required surgical treatment. The possible role and methods of treatment of cranial venous outflow obstruction in PTS are discussed.

Adult↗
PubMed2001

Assessing the comparative effectiveness of antidepressant therapies: a prospective clinical practice study.

BACKGROUND: Although efficacy studies suggest equal potency among antidepressant treatments, their effectiveness in clinical practice appears more variable, particularly in that the newer antidepressants may be less effective in either more severe depression or the melancholic subtype of depression. We pursue some factors that may impact the effectiveness of antidepressant treatments in a clinical sample. METHOD: A sample of 182 patients with DSM-IV major depressive disorder was assessed at baseline and 12 months later to establish treatments provided, identify patients who had recovered from the index episode, and quantify likely treatment determinants. Four systems for distinguishing patients with melancholic and non-melancholic depression were examined to assess for differential effects of the antidepressant strategies across those subtypes. RESULTS: Multimodal therapy (commonly, psychotherapy combined with an antidepressant drug) and patients' frequent attribution of recovery to spontaneous improvement made for difficulty in disentangling recovery determinants. After excluding a spontaneous improvement component, electroconvulsive therapy (ECT) and the irreversible monoamine oxidase inhibitors (MAOIs) appeared to be the most effective therapies across the sample, while the reversible inhibitor of monoamine oxidase-A (RIMA) appeared to be the least effective. The distinct gradient of suggested effectiveness of various strategies appeared to be contributed to principally by the varied effectiveness of alternate treatments across the melancholic subtype, whereby ECT, tricyclic antidepressants, and MAOIs were the most effective, and the selective serotonin reuptake inhibitors (SSRIs), RIMAs, and antipsychotic drugs were much less effective. For the nonmelancholic disorders, the effectiveness of SSRIs appeared to be comparable with that of older antidepressants. CONCLUSION: Although most patients received a physical treatment, they commonly judged psychotherapy and spontaneous improvement to be influential in their recovery. Reasons for such attributions are worthy of clarifying studies. Despite patients' concerns about the side effects and stigma of ECT as well as the side effects associated with the older antidepressants, these therapies were rated as more helpful by patients-and were more strongly associated with recovery-than the newer antidepressant drugs. Such overall results are compatible with an earlier study undertaken by us involving an independent sample and retrospective data. The overall gradient is clarified by studying depressive subtypes, allowing an important conclusion. Although the newer and older antidepressant drugs may be of similar effectiveness in nonmelancholic depression, the newer agents appear comparatively inferior for the treatment of melancholia, findings that have clinical implications and perhaps inform us about the pathogenesis of melancholia.

Adult↗
PubMed2001

Indicators of suicide over 10 years in a specialist mood disorders unit sample.

BACKGROUND: There are few firm data to guide the clinician in identifying individual depressed patients who may be at high risk for completing suicide. In particular, there have been few prospective studies of well-characterized depressed patients to determine indicators of such future events. METHOD: Eight hundred thirteen patients with a major depressive episode (DSM-III, DSM-III-R, or DSM-IV criteria) were assessed in detail in a specialist Mood Disorders Unit (MDU) over a 10-year period. Follow-up at the end of that period (mean = 5.1 years) confirmed that 31 patients (3.8%) had completed suicide. The suicide completers were compared on a broad range of clinical and demographic variables obtained at baseline with (1) the total remaining depressed sample, (2) 31 age- and sex-matched subjects who were confirmed to be alive and had never attempted suicide, and (3) 24 age- and sex-matched living subjects who had made at least 1 suicide attempt. RESULTS: The most consistent finding, across all 3 comparisons, was that the suicide completers were more likely to have been inpatients at the time of the index MDU assessment. Other characteristics of completers were a greater number of prior admissions for depression, being older and in a relationship, and being male and married or female and single. Somewhat paradoxically, suicide completers also evidenced fewer previous suicide attempts and less suicidal ideation compared with living subjects who had attempted suicide at the time of index assessment. CONCLUSION: Overall, we were able to find few predictors of later suicide in this sample. Those who completed suicide demonstrated evidence of more severe illness over a lifetime (for example, having more admissions). but revealed less suicidal ideation at the time of the index MDU assessment. While these features were statistically significant, they are of limited usefulness in predicting suicide in an individual patient.

Adult↗
PubMed2001

The development of a brief screening measure of emotional distress in children.

We report several studies developing a parent-rated measure of emotional distress for children in Singapore, with the key objectives being to derive a very brief valid measure of global distress. The refined item set comprised behaviourally expressed broad manifestations of emotional distress. Three developmental studies were undertaken, with the first two involving parental ratings on the measure for validation against clinician-rated distress levels, while also testing two rating options for the measure. We established clear comparative advantages to the rating anchors used in the Revised Rutter Scales. High inter-rater agreement was established across parental ratings, with the latter finding supporting objectives for the measure. Paternal scores correlated more strongly than maternal scores with clinician-generated distress scores. Additional properties of the measure were tested in a large community sample of nearly 2,000 Singapore schoolchildren in their last 2 years of primary school, allowing prevalence estimates and mean scores to be derived for each item. Here, girls and boys received identical total scores, scores were also independent of the number of children in the family and of ordinal position, and mothers returned higher scores than fathers.

Adolescent↗
PubMed2001

The clinical features of bipolar depression: a comparison with matched major depressive disorder patients.

BACKGROUND: Despite a resurgence of interest in the treatment of bipolar depression, there have been few controlled studies of the clinical characteristics of this condition. Identification of any distinctive clinical "signatures" of bipolar depression would be helpful in determining treatment options in the clinical setting. METHOD: From a cohort of 270 inpatients and outpatients assessed in detail during a DSM-IV major depressive episode, 39 bipolar I disorder patients were identified and closely matched with 39 major depressive disorder patients for gender, age, and the presence or absence of DSM-IV melancholic subtype. Patients were compared on a broad range of parameters including the Hamilton Rating Scale for Depression (depression severity), 54 depressive symptoms, the Newcastle Endogenous Depression Diagnostic Index, 3 family history items, 2 physical health items, the CORE scale (psychomotor disturbance), and 5 history items. RESULTS: Although the bipolar patients were no more severely depressed than the major depressive disorder controls, they were more likely to demonstrate psychomotor-retarded melancholic and atypical depressive features and to have had previous episodes of psychotic depression. These findings were largely duplicated even when the population was confined to those with DSM-IV melancholia. CONCLUSION: The clinical admixture of psychomotor-retarded melancholic signs and symptoms, "atypical" features, and (less frequently) psychosis may provide a "bipolar signature" in clinical scenarios when there is uncertainty concerning the polarity of a depressive presentation.

Adult↗
PubMed2001

Suicide in Singapore: a changing sex ratio over the last decade.

AIM OF STUDY: To examine for any change in the sex ratio of suicides in Singapore over the last decade. METHODS: Data on suicides in Singapore for the decade 1989-98 were examined, both as an overall set and as four age-based sub-groups. RESULTS: The male to female ratio increased significantly over the decade, contributed to most distinctly by changed rates in young adults (ie a group defined as 29-40 years). The changed sex ratio appeared limited to Chinese subjects, where the suicide rate/100,000 population was consistently higher than for the non-Chinese. The changed ratio appeared more to reflect an absolute decrease in female suicides rather than any distinct absolute increase in male suicides. CONCLUSIONS: The previous distinct male preponderance in suicide,which had progressively diminished by the early eighties, has become distinct again, but is now seemingly more driven by a disproportionate decline in the absolute rate of suicides in younger females. We speculate on possible social determinants of this intriguing epidemiological trend.

Adult↗
PubMed2001

A comparison of male and female theft offenders remanded to a state psychiatric hospital.

We report a retrospective study examining the prevalence, demographic profile and pattern of psychiatric morbidity of theft offenders remanded for psychiatric assessment by the Singapore courts. Case records of 100 male and 100 female consecutively remanded theft offenders were reviewed. There was a high rate of psychopathology, with schizophrenia as the commonest disorder. Sex differences were identified in demographic profiles, psychiatric diagnoses, types of offences committed and likely psychiatric determinants of the offence. Depression was more common in females while substance abuse and antisocial personality disorder were diagnosed more frequently in males.

Female↗
PubMed2001

Men who commit rape in Singapore.

INTRODUCTION: Rape is regarded as one of the most serious forms of sexual assault, yet there has been a lack of clinical information on convicted rapists in Singapore. This paper attempts to confirm the hypotheses that rapists come from disordered backgrounds, from large families and are poorly educated. We further hypothesize that they are more likely to have a history of antisocial behaviour and to have had recent exposure to pornography. METHODS: Rapists serving sentence in a Singapore prison were compared with 2 control groups, one consisting of violent non-sexual offenders and another comprising non-violent non-sexual offenders. RESULTS: Rapists tended to be men in their late thirties who rape women in their early twenties. A large majority of the rapists and their victims are known to each other. Rapists are more likely to come from large, disordered families, attaining low educational levels but seemingly less antisocial when compared with the controls. More rapists and violent controls reported recent viewing of pornography before committing their offenses. CONCLUSION: The demonstrated similarities between rapists and violent controls lend support to the view that rape is an act of violence carried out in a sexual manner rather than a sexual act violently expressed.

Adult↗
PubMed2001

The disability profile of patients with schizophrenia in psychiatric hospital and community settings in Singapore.

The disability profile of persons with schizophrenia in Singapore and how disability levels vary in patients cared for in the community and in the long-stay wards of a state mental hospital were studied using the Life Skills Profile (LSP). The inter-rater reliability of the LSP assessed by the intraclass correlation coefficient (ICC), was lower than in the Australian studies. The test-retest ICCs for the total LSP score and the five subscale scores were satisfactory for the hospitalised subjects and for the community psychiatric nurse subjects, but generally poor for the community care facility subjects. The average ICCs were lower compared to the Australian study. Female hospitalised subjects but not male hospitalised subjects returned higher disability scores on all LSP scales compared to community subjects. This study provided some preliminary data on the usefulness and validity of the LSP in a multi-ethnic Asian setting like Singapore. If the LSP is used as a measure of disability in schizophrenia, it would appear that ratings should only be made by those who know the subject well, and that raters should be formally trained mental health professionals.

Community Mental Health Centers↗
PubMed2000

Effect of apomorphine on motor and cognitive function in melancholic patients: a preliminary report.

Given the many clinical parallels between melancholia and disorders associated with impaired dopaminergic function such as Parkinson's Disease (PD), it has been hypothesised that major depressive disorder, and in particular the psychomotor features of melancholic depression, may also be associated with a hypodopaminergic state. If this is the case, then the use of a dopamine agonist might lead to reversal of both the cognitive and motor impairments seen in these patients. A double-blind, placebo-controlled cross-over design was used to test the effect of apomorphine on motor and cognitive function in seven melancholic subjects (as defined by the CORE instrument) and five control subjects. The testing battery included the following items: finger tapping, rapid alternating movements, verbal fluency, Rey Auditory Verbal Learning Task, digit symbol substitution task and simple and complex reaction times. The independent t-test, after covarying for age, revealed significant impairment in melancholic subjects for the walking task and digit symbol substitution at baseline. Results of the ANCOVA revealed no impact of time or drug condition, either alone or in combination, upon task performance in either group whether assessed separately or jointly. Results of a MANCOVA revealed that apomorphine impaired performance on some cognitive tasks, and that this was seen to a lesser extent in melancholics than control subjects. There was no evidence that the dopamine agonist apomorphine improved cognitive or motor function in subjects with strictly defined melancholia, suggesting that psychomotor retardation is not associated with a hypodopaminergic state. Our conclusions, however, were limited by small sample size; minimal baseline task impairment in depressed compared to control subjects; mild sedation in many subjects during task performance; and lack of serum apomorphine levels.

Aged↗
PubMed2000

Temporal changes in neuronal dropout following inductions of lithium/pilocarpine seizures in the rat.

Estimates of neuronal dropout for approximately 100 structures as defined by Paxinos-Watson were completed for brains of male Wistar albino rats between 1 and 50 days after status epilepticus was evoked by a single systemic injection of lithium and pilocarpine. Sample estimates of neuronal loss were strongly correlated with direct measures of cell density. The most extensive immediate damage occurred within the substantia nigra reticulata, CA1 field of the hippocampus, the piriform cortex and the reuniens and paratenial nuclei of the thalamus. Neuronal dropout continued in many other structures over a 50-day period. Structures that showed the greatest 2-deoxyglucose (2-DG) uptake during discrete seizures and waxing and waning seizures within the early stages of status epilepticus but the least 2-DG uptake at the time of late continuous spiking and fast spiking with pauses [Neuroscience 64 (1995) 1057, 1075] exhibited the most neuronal dropout. Relationships between the delay of injection of acepromazine (which facilitated survival) and the amount of damage suggested that the source of the process that results in permanent brain damage may originate within the region of the piriform cortices and its subcortices.

Animals↗