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P Mitchell

Publications and source records attributed to P Mitchell.

At least 343 records · Page 19Linked to original sources
PubMed1995

Realism and children's early grasp of mental representation: belief-based judgements in the state change task.

In a standard deceptive box procedure, children aged around 3 years typically fail to acknowledge their own prior false beliefs. For example, they judge incorrectly that they had initially thought a Smarties tube contained pencils after discovering these to be the actual content. Wimmer and Hart (1991) showed that children were more likely to answer correctly in a variant of this task known as a "state change", procedure. In this task, they saw that a container held its expected content (so the initial belief was true) before this was exchanged for something atypical. This appears to offer powerful evidence suggesting that children who fail the standard task do not understand about belief. However, we argue against this view. In a series of 4 experiments, we show that when children see the expected contents before these are swapped for something atypical, this not only makes it easier to report their own and a puppet's initial true belief but also a puppet's current false belief. The results are consistent with the "reality masking hypothesis", according to which facilitation is due to the belief option being linked with a physical counterpart in the state change procedure.

Child, Preschool↗
PubMed1995

Biochemical correlates of in vivo cell-mediated immune dysfunction in patients with depression: a preliminary report.

We have previously demonstrated that at least 50% of patients with melancholia have impaired cell-mediated immunity (CMI) as assessed by delayed-type hypersensitivity (DTH) skin responses to a standardized battery of antigens. Hypercortisolaemia and increased circulating catecholamines both occur in patients with severe depressive disorders and each has been proposed as a possible mediator of observed immune abnormalities in patients with mood disorders. As part of a larger study, we collected 24 h urine samples from 28 patients with major depression and measured concentrations of urinary free cortisol (UFC), the noradrenaline metabolite dihydroxyphenylglycol (DHPG), adrenaline, and the dopamine metabolite DOPAC. CMI multitest skin testing revealed a reduced or absent response in 54% of subjects. Those with reduced DTH skin responses demonstrated increased urinary adrenaline (P < 0.02), with trends toward increased UFC (P = 0.052) and increased DHPG (P = 0.06). These differences could not be attributed to differences in age or depression severity. Correlational analyses demonstrated inverse associations between the extent of DTH responsiveness and 24 h levels of urinary adrenaline and DHPG, with similar trends evident for UFC and DOPAC. These results suggest that both circulating catecholamines and cortisol may play roles in the reduction of CMI in patients with severe depression.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Prevalence of age-related maculopathy in Australia. The Blue Mountains Eye Study.

PURPOSE: To examine the prevalence of age-related maculopathy (drusen and retinal pigmentary abnormalities) and end-stage age-related macular degeneration lesions (neovascular maculopathy or geographic atrophy) in a defined older Australian urban population. SUBJECTS: All noninstitutionalized residents 49 years of age or older who were identified in a door-to-door census of two postcode areas west of Sydney, Australia. METHODS: All participants received a detailed eye examination, including stereoscopic photographs of each macula. Two trained graders used the Wisconsin Age-related Maculopathy Grading System to assess the presence and severity of typical lesions. RESULTS: A marked age-related increase in all typical lesions of age-related maculopathy and macular degeneration was observed. End-stage age-related macular degeneration was present in 1.9% of the population, rising from 0% among people younger than 55 years of age to 18.5% among those 85 years of age or older. Soft drusen were found in 13.3% of people, with distinct drusen more frequent than indistinct soft drusen. Retinal pigmentary abnormalities were found in 12.6% of people. For end-stage lesions and soft drusen, females had higher age-specific prevalence rates than males, whereas retinal pigmentary abnormalities were more frequent in males, although most of these differences were not significant. Prevalence rates for all lesions were lower (statistically significant for retinal pigmentary abnormalities and soft drusen) than for the United States Beaver Dam Eye Study which examined a similar population. CONCLUSIONS: These data provide detailed prevalence rates for most components of ARM in an Australian population and reinforce the Beaver Dam Eye Study findings for the relative age-specific frequency of age-related macular degeneration components.

Age Distribution↗
PubMed1995

Sub-typing depression, I. Is psychomotor disturbance necessary and sufficient to the definition of melancholia?

Melancholia is most commonly distinguished from non-melancholic depression by the presence of psychomotor disturbance (PMD) and a set of 'endogeneity' symptoms. We examine the capacity of an operationalized clinician-rated measure of PMD (the CORE system) to predict diagnostic assignment to 'melancholic/endogenous' classes by the DSM-III-R and Newcastle systems. Examining a pre-established CORE cut-off score (> or = 8) against independent diagnostic assignment, PMD was present in 51% of those assigned as melancholic by DSM-III-R, and 85% of those assigned as endogenous by the Newcastle system, quantifying the extent to which it is 'necessary' to the two definitions of 'melancholia'. Additionally, multivariate analyses established that the addition of a refined set of historically suggested endogeneity symptoms added only slightly to overall discrimination of melancholic and non-melancholic depressives. While only few endogeneity symptoms independent of psychomotor disturbance were suggested, their specific relevance varied against system definition of melancholia (appetite/weight loss and terminal insomnia being identified for DSM-III-R; anhedonia for Newcastle; and diurnal variation in mood and energy for both systems). Results allow consideration of the relative importance of two domains (psychomotor disturbance and 'endogeneity' symptoms) to clinical definition of melancholia, and have the potential to assist both classification and pursuit of neurobiological determinants. We interpret findings as suggesting a 'core and mantle' model for conceptualizing the clinical features of melancholia, with psychomotor disturbance as the core and with independent endogeneity symptoms as only a thin mantle.

Adult↗
PubMed1995

Sub-typing depression, II. Clinical distinction of psychotic depression and non-psychotic melancholia.

We have attempted to clarify clinical differentiating features of psychotic depression. Forty-six depressed subjects meeting DSM-III-R criteria for major depression with psychotic features were compared with (i) DSM-defined melancholic, (ii) Newcastle-defined endogenous, and (iii) a residual DSM-defined major depressive episode group. Additionally, a 'bottom up' latent class analysis (LCA) suggested a larger sample of 82 'psychotic depressive' subjects, and multivariate analyses contrasted these subjects with both LCA-identified melancholic and all residual depressed subjects. Analyses suggested that, in addition to two features with absolute specificity (delusions and hallucinations), both the DSM-defined and LCA-defined 'psychotic depressive' subjects were significantly more likely to demonstrate marked psychomotor disturbance, to report two morbid cognitions (feeling sinful and guilty; feeling deserving of punishment), as well as be more likely to report constipation, terminal insomnia, appetite/weight loss and (variable across the defined 'psychotic depressive' groups) loss of interest and pleasure. The study identifies a wider set of potentially discriminating clinical variables than previous studies, as well as both indicating the existence and assisting identification of 'true' psychotic depression in the absence of formal psychotic features being acknowledged or elicited.

Adult↗
PubMed1995

Sub-typing depression, III. Development of a clinical algorithm for melancholia and comparison with other diagnostic measures.

We describe the development of a clinical algorithm to differentiate melancholic from non-melancholic depression, using refined sets of 'endogeneity' symptoms together with clinician-rated CORE scores assessing psychomotor disturbance. Assignment by the empirically developed algorithm is contrasted with assignment by DSM-III-R and with several other melancholia sub-typing indices. Both the numbers of 'melancholics' assigned by the several systems and their capacity to distinguish 'melancholics' on clinical, demographic and a biological index test (the DST) varied across the systems with the algorithm being as 'successful' as several systems that include inter-episode and treatment response variables. Analyses provide information on the criteria set developed for DSM-IV definition of 'melancholia'.

Adult↗
PubMed1995

Young children's treating of utterances as unreliable sources of knowledge.

In two investigations (N = 62 and 59), three- and four-year-old children sometimes disbelieved what they were told about the unexpected contents of a deceptive box, even when they had seen the adult speaker look inside the box before s/he told them what s/he saw, and despite being able to recall the utterance: utterances were treated as unreliable sources of knowledge compared with seeing directly. Those who did believe the utterance were no better at recalling their prior belief about the box's contents (now treated as false), than those who saw inside the box. However using a narrative procedure, we replicated Zaitchik's (1991) result that children are more likely to acknowledge another's belief when they are told about reality, than when they see reality for themselves. We argue that these children were acknowledging alternative rather than false belief.

Child Language↗
PubMed1995

Platinum-Taxol non-cross resistance in epithelial ovarian cancer.

The aim of this study was to assess the clinical evidence for platinum-Taxol non-cross-resistance in patients with epithelial ovarian cancer. Unlike other studies, only patients who had demonstrably progressive disease on platinum therapy were analysed. Patients received 135-200 mg m-2 of Taxol over 3 or 24 h and all patients were assessed for response by computerised axial tomography. The overall response rate was 22.2% (8/36 patients, 95% CI 10-39%). Only patients who received > or = 175 mg m-2 of Taxol responded (26.7%; 8/30 patients, 95% CI 12-46%). No complete responses were seen and the duration of response was short, median 7 months (range 5-9+). Response was associated with a short treatment-free interval (P = 0.02); only those who were treated immediately after they had progressed on their previous platinum therapy responded. Response duration was associated with a good performance status (P < 0.05). Platinum and Taxol are non-cross-resistant in a proportion of patients and therefore patients who are resistant to platinum compounds may benefit from Taxol although the duration of any response is short. These data support current strategies that involve combining Taxol with platinum compounds as first-line therapy in advanced epithelial ovarian cancer.

Adult↗
PubMed1995

Corn oil and beef tallow elicit different postprandial responses in triglycerides and cholesterol, but similar changes in constituents of high-density lipoprotein.

OBJECTIVE: The study was designed to compare, in a homogeneous, normolipidemic population, the postprandial responses of plasma lipids, in particular, high-density lipoprotein (HDL) constituents, after administration of a polyunsaturated fat and a more saturated fat. METHODOLOGY: Emulsions of 100 g corn oil (CO) and 100 g beef tallow (BT) were given in a crossover protocol to 12 male subjects (21-24 years). Plasma cholesterol (TC), triglycerides (TG), and HDL lipid and protein constituents were measured at 0, 2, 4, 7 and 10 hours. RESULTS: A postprandial increase in TG at 2 hours after CO ingestion (96%) was twice that with BT (48%); TG returned to near fasting levels at 10 hours after ingestion of either fat. Areas under the TG response curves for CO and BT were 6.29 +/- 1.67 and 1.75 +/- 0.60 mmol x hour/L (mean +/- SE), respectively. TC and low-density lipoprotein cholesterol (LDL-C) levels were unchanged at 10 hours after CO ingestion, but they were increased 8.1% and 9.3%, respectively, with BT. Both fats increased HDL TG at 2-4 hours, and both similarly increased HDL free cholesterol, cholesterol ester, phospholipid, apolipoproteins A-I and A-II, and lipoprotein (A-I) levels at 7-10 hours. Changes in HDL were predominantly in HDL3. CONCLUSIONS: The increase in LDL-C with BT at 10 hours suggests that levels may be abnormally elevated in "fasting" samples, dependent on the amount and type of fat in a prior meal. The increase in LDL-C is consistent with short-term regulation of hepatic LDL-receptor activity and/or LDL synthesis. Similar increases in HDL constituents at 7-10 hours after CO or BT, despite the difference in TG responses, suggests differences in the metabolism of chylomicrons and/or HDL due to the type of fat ingested.

Adult↗
PubMed1995

Agenesis and dysgenesis of the sacrum: neurosurgical implications.

We reviewed 27 patients with congenital anomalies of the sacral spine. There were 16 males and 11 females with a mean follow-up of 81.1 months (range 8-211 months). Fifteen patients had sacral agenesis and 12 had sacral dysgenesis. Fifteen patients had neuroimaging of the spine. Seven patients had conus termination below the L2 vertebral body. Four patients had associated thoracic syringomyelia and 6 patients were identified with caudal or dorsal lipoma. There were only two episodes of neurological deterioration, both in a single patient who had a lipomyelomeningocele, in 182 patient-years of follow-up. Four patients with low lying conus had pre-emptive spinal cord exploration for release of tethering in order to prevent neurological deterioration. Patients with agenesis or dysgenesis of the sacrum should undergo magnetic resonance (MR) imaging of the spine in order to detect spinal cord lesions associated with progressive neurological deterioration. Findings on MR imaging are more likely to correlate with clinical course than findings on skeletal radiography.

Abnormalities, Multiple↗
PubMed1995

Fitting the treatment to the patient: recent advances in the practice of electroconvulsive therapy.

Traditionally it has been thought that a grand mal seizure is both necessary and sufficient for the maximum efficacy of ECT. Recent important research, however, has demonstrated that both the electrical dosage above the seizure threshold, i.e. the suprathreshold dosage, and the electrode placement (unilateral or bilateral) determine the efficacy of this treatment, as well as the degree of cognitive impairment. This article reviews the development of these significant concepts and suggests specific practical recommendations for incorporating these into contemporary ECT practice.

Cerebral Cortex↗
PubMed1995

Validating a model developed to predict prenatal care utilization.

BACKGROUND: Many pregnant women in the United States do not obtain adequate prenatal care. While it is essential to provide women with access to prenatal care, access alone is insufficient to guarantee that all women will receive adequate prenatal care. Previous research has identified a number of personal and cultural barriers to prenatal care. We have integrated these barriers into an explanatory model called the Social Pregnancy Interaction Model, the centerpiece of which is the concept of a "social pregnancy identity," as distinct from the physiologic reality of pregnancy. The purpose of this study was to validate the dimensions of this model. METHODS: Based on previous qualitative work, a questionnaire was developed. It was administered by interview to a convenience sample of 287 pregnant women receiving prenatal care in 11 practices in central Missouri. Item analysis and factor analysis were used to define scales and validate the relationships predicted by the model. RESULTS: With some modifications, the following dimensions of the model were confirmed as distinct and significant: awareness of pregnancy, acceptance of pregnancy, self-care, communication with family, communication with partner, social attitudes toward prenatal care, and attitudes toward the health care provider. CONCLUSIONS: The model has potential for predicting the utilization of prenatal care. The results also suggest that a woman's relationship with her prenatal care provider is important to obtaining adequate prenatal care.

Adolescent↗
PubMed1995

MR and cognitive testing of patients undergoing osmotic blood-brain barrier disruption with intraarterial chemotherapy.

PURPOSE: To determine whether osmotic blood-brain barrier disruption is associated with MR abnormalities or cognitive deterioration and, if so, whether the MR findings correlate with cognitive test results. METHODS: Fifteen brain tumor patients who had a complete tumor response (nine central nervous system lymphoma, three germ cell and two astrocytoma, and one primitive neuroectodermal tumor) treated with blood-brain barrier disruption procedures (318 total procedures) with intraarterial chemotherapy were included. MR images were evaluated for the development of white matter hyperintensity, vascular lesions, or atrophy. Cognitive testing was performed to assess deterioration caused by this therapy. RESULTS: In two patients white matter hyperintensity developed, in two small vascular lesions developed, and in one mild atrophy developed. One infarct was asymptomatic and the second one resulted in mild dysesthesia in one upper extremity. No patient showed diminished cognitive function on the posttherapy evaluation. CONCLUSION: In patients undergoing blood-brain barrier disruption with intraarterial chemotherapy, new abnormalities on MR imaging may develop. These patients maintain the same level of cognitive and neurologic function and MR findings do not correlate with the results of cognitive testing.

Adolescent↗
PubMed1994

A case control study to determine risk factors for campylobacter infection in Christchurch in the summer of 1992-3.

AIM: This study was designed to determine the risk factors for acquiring campylobacter infection in Christchurch in the summer of 1992/3. METHODS: A case control study was conducted of 100 cases and controls from urban areas matched for age and sex. Cases and controls were interviewed by telephone using a questionnaire and results analysed using the Epi Info statistical computer programme. RESULTS: Eighty one percent of both cases and controls had recently consumed poultry. Eating poultry at a friends house (OR = 3.18, CI 1.0, 10.73, p = 0.03), at a barbecue (OR = 3.00, CI 0.99, 9.34, p = 0.03) or eating undercooked chicken (OR = 4.94, CI 1.03, 23.62, p = 0.05) was a risk whereas eating at home was protective (OR = 0.36, CI 0.14, 0.9, p = 0.02). Other factors associated with increased risk were drinking water from a nonurban supply (OR = 2.7, CI 0.89, 8.33, p = 0.09) or consumption of chicken bought fresh (OR = 1.8, CI 0.85, 3.82, p = 0.10). CONCLUSION: Poorly cooked or handled chicken is a significant source of human campylobacter infection. Morbidity may be reduced by increased public awareness and improvement of cooking practices.

Adolescent↗