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Biomedical subjects

S Cathcart

Publications and source records attributed to S Cathcart.

15 recordsLinked to original sources
PubMed2001

Schizophrenia-like psychosis following traumatic brain injury: a chart-based descriptive and case-control study.

BACKGROUND: Head injury has been reported to increase the likelihood of the development of schizophrenia-like psychosis (SLP), but its features and risk factors have been insufficiently investigated. METHOD: Between 1987 and 1997, we examined 45 referred patients with SLP following brain trauma. These subjects were matched with 45 head-injured subjects without SLP on age (current and at injury) and gender, and their case records reviewed systematically. The groups were compared and logistic regression analyses performed. RESULTS: The psychoses had a mean age of onset of 26.3 years, a mean latency of 54.7 months after head injury, usually a gradual onset and a subacute or chronic course. Prodromal symptoms were common and depression often present at onset. Paranoid delusions and auditory hallucinations were the predominant features, with formal thought disorder, catatonic features and negative symptoms being uncommon. The SLP group had more widespread brain damage on neuroimaging, especially in the left temporal and right parietal regions, and were more impaired cognitively. Fewer (non-significantly) SLP subjects had epilepsy which was more likely to be well-controlled in this group. On regression analysis, a positive family history of psychosis and duration of loss of consciousness were the best predictors of SLP. CONCLUSIONS: Head injury-related psychosis is usually paranoid-hallucinatory and subacute or chronic in its presentation. A genetic predisposition to schizophrenia and severity of injury with significant brain damage and cognitive impairment may be vulnerability factors.

Adolescent↗
PubMed2000

Anger, depression, and coping interactions in headache activity and adjustment: a controlled study.

OBJECTIVE: To determine if individuals in the general community with chronic headache or migraine differ in terms of anger, depression, and coping strategies and from headache-free individuals in terms of anger and depression. METHOD: A community sample comprising 16 chronic tension-type headache (CTH), 28 migraine headache (MH), and 38 headache-free control subjects (CNT) were compared on measures of anger, depression, and use of various coping strategies. Affective and coping measures, recorded during a headache-free period, were regressed on headache activity measured in a daily diary over the following 2 weeks. Relationships between anger, depression, and coping were also examined in each of the headache groups. RESULTS: The MH subjects were found to use less effective coping strategies than controls and CTH, while the CTH group had higher levels on depression and various anger scales compared to controls and MH. Direct positive relationships were observed between suppressed anger and depression in the MH group, and between trait anger and depression in the CTH group. Anger and coping were predictive of headache activity in the following 2 weeks for both MH and CTH groups, while depression and coping, compared to coping only, were predictive of lifestyle interference from head pain in MH and CTH, respectively. CONCLUSION: The results support a relationship between affective and coping factors in headache activity and adjustment.

Adaptation, Psychological↗
PubMed2000

Hippocampus and amygdala volumes in elderly schizophrenic patients as assessed by magnetic resonance imaging.

Reduced size of the hippocampus and amygdala has been one of the more consistent morphological findings in schizophrenia, but the question of medial temporal abnormalities in elderly schizophrenia patients has been inadequately addressed. We examined 20 elderly subjects with a DSM-III-R diagnosis of schizophrenia, five of whom had a late-onset schizophrenia (LOS), and compared them with 20 healthy volunteers on magnetic resonance imaging (MRI) and neuropsychological parameters. Hippocampus and amygdala volumes were obtained by manual tracing on T1-weighted 1.5 mm thick contiguous coronal slices perpendicular to the long axis of the hippocampus. Patients had smaller left hippocampal and right amygdala volumes than comparison subjects, the mean differences being 9.7 and 11.1%, respectively, but the right amygdala volumes were not significantly different after Bonferroni correction. The hippocampus-amygdala volumes together were smaller in the schizophrenia group bilaterally. In a pilot analysis, the LOS subjects had non-significantly smaller hippocampus-amygdala volumes than did the early-onset schizophrenia (EOS) subjects. For the schizophrenia group, there were significant correlations between amygdala and hippocampus volumes and some neuropsychological performance indices. The findings are consistent with those reported in younger schizophrenics, and are of the same order of magnitude, suggesting that they are not likely to be progressive. This pilot analysis in LOS subjects argues against the condition being secondary to Alzheimer's disease.

Age Factors↗
PubMed1999

Reliability and validity of ratings of signal hyperintensities on MRI by visual inspection and computerised measurement.

Brain magnetic resonance imaging (MRI) scans on 98 elderly subjects, 62 with a diagnosis of schizophrenia and 36 healthy controls, were independently and blindly rated by two investigators using the visual rating methods of Fazekas et al. (Fazekas, F., Chawluk, J.B., Alavi, A., Hurtig, H.I., Zimmerman, R.A., 1987. MR signal abnormalities at 1.5 T in Alzheimer's dementia and normal aging. American Journal of Neuroradiology 8, 421-426) and Victoroff et al. (Victoroff, J., Mack, W.J., Grafton, S.T., Schreiber, S.S., Chui, H.C., 1994. A method to improve interrater reliability of visual inspection of brain MRI scans in dementia. Neurology 44, 2267-2276) for periventricular, deep white matter and subcortical gray matter signal hyperintensities (SHs) on T2-weighted images. The hyperintense signal volumes were measured by manual delineation of the signals on a workstation using Analyze software (computerised method). The subjects also underwent a detailed neuropsychological assessment. There was a high correlation between two experienced raters for both visual ratings, and the correspondence between the two methods was high. The inter-rater reliability for the computerised method was modest but significant, and the association between the visual and computerised methods was good except for ratings for SHs in subcortical nuclei. The Fazekas and computerised methods, and to a lesser degree the Victoroff method, had modest but significant correlations with some neuropsychological test measures. In conclusion, we did not demonstrate a clear superiority in reliability or validity for one demanding computerised method of rating SHs. Visual ratings should therefore be considered adequate for most clinical and research purposes, but such ratings should be accompanied by adequate training and the provision of standard reference images.

Aged↗
PubMed1999

The preventative role of antioxidants (selegiline and vitamin E) in a rat model of tardive dyskinesia.

BACKGROUND: We examined the potential protective effects of two potent antioxidants, selegiline and vitamin E, in a rodent model of tardive dyskinesia (TD), viz. neuroleptic-induced spontaneous orofacial movements. METHODS: Rats were treated with fortnightly injections of fluphenazine decanoate for 12 weeks, and examined at baseline and at fortnightly intervals for vacuous chewing movements, mouth tremors and tongue protrusions. RESULTS: The administration of fluphenazine led to a progressive increase of all three types of orofacial movements. In the first study, the impact of the concomitant administration of selegiline on orofacial movements was examined. Selegiline led to a reduction in orofacial movements in neuroleptic-treated rats to the level of control rats not being administered a neuroleptic drug. In the second study, rats were fed diets either high or low in their vitamin E content. High and low vitamin E diets did not significantly affect neuroleptic-induced orofacial movements. CONCLUSIONS: Our studies provide some support for the hypothesis that oxidative injury may play a role in the genesis of neuroleptic-induced movement disorder, and prompt further examination of this hypothesis in both animals and humans.

Animals↗
PubMed1999

Time-series analyses of general arousal and headache activity in the natural environment.

A naturalistic longitudinal study was conducted to examine temporal relationships between subjective dimensions of general arousal and headache activity. The "tense arousal" dimension of Thayer's biopsychological model of mood and arousal (The Biopsychology of Mood and Arousal. New York: Oxford University Press; 1989) was recorded using the Activation-Deactivation Adjective Check List (ADACL). Recordings were made eight times daily, every 2 hours from awakening, in conjunction with a clinical diary recording head pain intensity and duration. Three time series of daily, half-daily, and bihourly headache and tension scores were modeled and cross-correlated. Results indicated moderate positive same-time correlations, but revealed large interindividual and intraindividual variation in temporal relationships.

Adult↗
PubMed1999

Headache interference as a function of affect and coping: an artificial neural network analysis.

Artificial neural networks present a technique for modeling relationships between variables in complex systems. The negative effects of headache are determined by many "biopsychosocial" elements that represent a complex system. Artificial neural networks may therefore be useful for examining psychological factors in headache. To test this hypothesis, we trained an artificial neural network to predict life-style interference attributed to headache from psychological measures of anger, depression, and coping appraisal and strategies. The artificial neural network demonstrated a better fit of the data than that obtained by multiple regression, and predicted interference levels to within 10% error for 80% of novel cases. Artificial neural networks may be a useful technique for examining psychological correlates of headache.

Adaptation, Psychological↗
PubMed1999

Schizophrenia with onset after age 50 years. 2: Neurological, neuropsychological and MRI investigation.

BACKGROUND: Late-onset schizophrenia (LOS) may have a basis in age-related coarse brain disease, but empirical support for this is conflicting. AIMS: Is LOS characterised by more neurological disease than early-onset schizophrenia (EOS)? METHODS: DSM-III-R-defined LOS subjects (n = 27) were compared with 30 EOS and 34 volunteer control subjects on neurological status, neuropsychological test performance and brain magnetic resonance imaging (MRI). RESULTS: LOS and EOS groups had more 'soft' neurological signs and drug-induced movement abnormalities, and performed more poorly on tests assessing speed of information processing, memory and frontal executive functioning. On MRI, the LOS and EOS groups had greater lateral ventricular size than the control group. The LOS subjects also had more signal hyperintensities in periventricular white matter and subcortical nuclei than controls. CONCLUSIONS: LOS and EOS subjects were very similar on neuropsychological, neurological and structural neuroimaging parameters, except that there were more MRI periventricular hyperintensities in LOS subjects.

Age of Onset↗
PubMed1998

Relationships between arousal-related moods and episodic tension-type headache: a biopsychological study.

An exploratory study was conducted examining arousal-related moods and episodic tension-type headache. Twelve subjects meeting International Headache Society criteria for episodic tension-type headache and 12 headache-free controls recorded headache activity and mood eight times daily for 14 consecutive days. Moods were measured using the Activation-Deactivation Adjective Check List, a self-report list that subjectively represents general arousal along two dimensions of Tension and Energy. Headache subjects had higher Tension levels than controls even in the absence of pain, and greater variation in this dimension as well. Within the headache group, Tension during pain-free periods was significantly lower than when experiencing headache, and was correlated with headache activity. The results were taken to support Thayer's (1989) biopsychological model of mood and arousal, and are discussed in terms of the model's heuristic value for general arousal and headache research.

Adult↗
PubMed1998

Factors in human serum interfere with the measurement of advanced glycation endproducts.

Advanced glycation endproducts (AGEs) have been implicated in the pathophysiology of coronary heart disease in ageing, diabetes and renal disease. Competitive enzyme-linked immunosorbent assays (ELISAs) have been developed to measure these compounds in serum, but as recognition of AGEs is both carrier protein- and antibody-dependent standardisation is problematic. We report here on another barrier to standardization, as yet unrecognised. During the development of an AGE ELISA, we found that serum samples did not dilute in parallel to AGE standards or each other. This finding was confirmed by recovery studies that showed over-recovery of AGEs at high serum concentrations, but under-recovery at high dilutions of serum in assay buffer. We developed an inhibition assay to detect factors in serum capable of interacting directly with AGEs immobilised on microtitre plates. Binding of these factors prevented recognition of AGEs by a CML monoclonal antibody and a polyclonal anti-AGE antibody, and was neither sugar- nor carrier protein-dependent. We detected the presence of this factor in all human sera tested and also in foetal calf serum. Pre-incubation of sera with AGEs or heat-treatment at 56 degrees C for 30 min. significantly reduced this binding. We are currently investigating the nature of this factor and the possibility that it may be complement. The effect of this factor on immunoassays for AGEs can only be detected by performing parallelism and recovery studies and we suggest the use of the method referred to in this paper to aid interpretation of parallelism data.

Antibodies↗
PubMed1994

Low-density lipoprotein particle size in type 2 diabetic patients and age matched controls.

Non-enzymatic glycation of low-density lipoprotein (LDL), and the predominance of small dense LDL particles may together contribute to the increased risk of atherosclerosis in diabetes. We aimed to establish whether the size of LDL particles is related to plasma triglyceride concentration, and to the extent of LDL glycation in type 2 diabetic patients. Sixteen men with type 2 diabetes and 16 age matched non-diabetic controls were studied. LDL size was measured by rapid density gradient ultracentrifugation, and LDL glycation by affinity chromatography. Modal LDL density correlated with plasma triglyceride concentrations in both diabetic and control groups (r = 0.86, P < 0.0001, and r = 0.76, P < 0.0008, respectively). There was no significant difference in these variables between the groups. LDL modal density showed no correlation with HbA1, serum fructosamine or plasma glucose in either group. In the diabetic group the degree of LDL glycation correlated with serum fructosamine (r = 0.74, P < 0.001), HbA1 (r = 0.65, P < 0.008), and with plasma glucose (r = 0.64, P < 0.008). Our results suggest that, in well controlled type 2 diabetic patients LDL size is independent of short-term glycaemic control but can be predicted by plasma triglyceride concentrations.

Adult↗
PubMed1990

Elevation of blood lactate and pyruvate levels in acute intermittent porphyria--a reflection of haem deficiency?

Blood lactate concentrations after glucose loading were significantly higher in 6 patients with acute intermittent porphyria in clinical remission than in 6 control subjects and the percentage rise in glucose pyruvate and lactate concentrations were greater in the porphyric subjects than in the control group. It is postulated that the raised lactate levels in the porphyric patient group may reflect haem deficiency affecting the cytochromes of the terminal respiratory chain.

Adult↗
PubMed1990

The measurement of lipoprotein subfractions in plasma using a tabletop ultracentrifuge.

We adapted the ultracentrifugation method of the Lipid Research Clinics Program for the separation of lipid subfractions (LDL, VLDL and HDL cholesterol) to a tabletop ultracentrifuge (Beckman TL-100). Centrifugation time was reduced from 18 h to 2.5 h and the sample volume from 5 mL to 2 mL plasma. The imprecision of the LDL-cholesterol estimation (coefficient of variation = CV) was 2.9-7.4% and that of HDL-cholesterol measurement was 1.4-3.9%. Imprecision of the VLDL-C measurement was high (CV = 15.6-29.8%). The results correlated with those obtained by the Lipid Research Clinics method (P less than 0.001). Our method could be conveniently adapted by clinical laboratories serving specialist lipid clinics.

Cholesterol↗