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B K Puri

Publications and source records attributed to B K Puri.

At least 55 records · Page 3Linked to original sources
PubMed1999

Volumetric change of the lateral ventricles in the human brain following glucose loading.

Lateral ventricular volumes were monitored and quantified using accurately registered magnetic resonance images (MRIs) in six healthy individuals 30 min before and up to 4 h after ingestion of a glucose drink. The volume of the lateral ventricles increased by an average (+/- S.E.M.) of 2.4 +/- 0.4% as blood glucose levels rose from 4.8 +/- 0.2 mmol l-1 to 8.4 +/- 0.4 mmol l-1. This was followed by a peak decrease of 5.99 +/- 3.3% below initial fasting volumes as blood glucose levels fell to 5.0 +/- 0.3 mmol l-1. We suggest that the secondary volume decrease demonstrates a homeostatic process of brain volume regulation for which the mechanism remains uncertain.

Administration, Oral↗
PubMed1999

Spontaneous dyskinesia in first episode schizophrenia.

In the west London prospective study of first episode schizophrenia, the prevalence and nature of abnormal involuntary movements were examined in 27 patients who had never received antipsychotic drugs and 36 who had been treated with such medication. Motor disturbance was assessed with rating scales designed to cover the full range of spontaneous and drug induced movement disorder. Only one person in the drug naive group showed evidence ofparkinsonism, a finding which contrasts with recent reports suggesting that spontaneous extrapyramidal signs may not be uncommon in such patients. However, according to ratings on the modified Rogers scale, 11% of the drug naive group exhibited orofacial dyskinesia, 4% trunk and limb dyskinesia, 7% postural abnormalities, and 4% increased muscle tone. The respective figures in the closely matched medicated group were not significantly different except for increased muscle tone, which was significantly more common (25%). The proportion of drug naive patients fulfilling criteria for tardive dyskinesia on the abnormal involuntary movements scale ranged from 4% to 11% depending on the criterion threshold score used. These findings are in accord with the notion that abnormal involuntary movements, particularly orofacial dyskinesia, represent a neuromotor component of schizophrenia.

Adolescent↗
PubMed1998

Two methods for semi-automated quantification of changes in ventricular volume and their use in schizophrenia.

Two semi-automated methods for quantification of ventricular volume change from baseline and follow-up magnetic resonance imaging scans have been developed. Technique 1 employs direct segmentation of the ventricles from both the scans using thresholding and contour extraction. Technique 2 operates on difference images produced by voxel based intensity subtraction of the baseline from the registered follow-up images. Here, all voxels with intensities above a noise threshold and in a restricted area are monitored to compute volumetric changes. In phantom measurements the first technique was accurate to 0.0046%, the second to 0.167% of the phantom volume. Results from normal volunteers was that the average ventricular volume changed by 1.52% and 1.54% for images acquired within 9 months using techniques 1 and 2, respectively. With schizophrenic patients mean change of 10.78% and 9.43% were found employing the first and second procedures, respectively. All measurements agreed with a radiologist's visual grading of the changes. Robust, objective, fast, easy-to-use, and fairly accurate procedures have been developed and validated to quantify volumetric changes.

Adult↗
PubMed1998

Executive function in first-episode schizophrenia.

BACKGROUND: We tested the hypothesis that schizophrenia is primarily a frontostriatal disorder by examining executive function in first-episode patients. Previous studies have shown either equal decrements in many cognitive domains or specific deficits in memory. Such studies have grouped test results or have used few executive measures, thus, possibly losing information. We, therefore, measured a range of executive ability with tests known to be sensitive to frontal lobe function. METHODS: Thirty first-episode schizophrenic patients and 30 normal volunteers, matched for age and NART IQ, were tested on computerized test of planning, spatial working memory and attentional set shifting from the Cambridge Automated Neuropsychological Test Battery. Computerized and traditional tests of memory were also administered for comparison. RESULTS: Patients were worse on all tests but the profile was non-uniform. A componential analysis indicated that the patients were characterized by a poor ability to think ahead and organize responses but an intact ability to switch attention and inhibit prepotent responses. Patients also demonstrated poor memory, especially for free recall of a story and associate learning of unrelated word pairs. CONCLUSIONS: In contradistinction to previous studies, schizophrenic patients do have profound executive impairments at the beginning of the illness. However, these concern planning and strategy use rather than attentional set shifting, which is generally unimpaired. Previous findings in more chronic patients, of severe attentional set shifting impairment, suggest that executive cognitive deficits are progressive during the course of schizophrenia. The finding of severe mnemonic impairment at first episode suggests that cognitive deficits are not restricted to one cognitive domain.

Adolescent↗
PubMed1998

Smooth pursuit and saccadic abnormalities in first-episode schizophrenia.

BACKGROUND: Previous studies of oculomotor dysfunction in schizophrenia have tended to concentrate on abnormalities of smooth pursuit eye tracking in chronic medicated patients. We report the results of a study of smooth pursuit, reflexive and antisaccade performance in drug naive and antipsychotic treated first-episode schizophrenic patients. METHODS: Smooth pursuit and saccadic eye movements were recorded in 36 first-episode schizophrenic patients and 36 controls matched for age and estimated IQ. The schizophrenic patients were divided into drug-naive (N = 17) and antipsychotic treated groups (N = 19). RESULTS: Smooth pursuit velocity gain was significantly lower than controls only in the drug-naive patients. The treated patients did not differ significantly from either the controls or the untreated group. In an antisaccade paradigm both treated and drug-naive schizophrenic patients demonstrated an increased number of errors, but only drug-naive patients also demonstrated an increased latency in initiating correct antisaccades. CONCLUSIONS: These impairments are unlikely to be due to a generalized deficit in oculomotor function in the schizophrenic groups, as there were no differences between the groups in saccadic metrics on a reflexive saccade task. The results show that both smooth pursuit and saccadic abnormalities are present at the onset of schizophrenia and are integral to the disorder.

Adolescent↗
PubMed1998

The human motor cortex after incomplete spinal cord injury: an investigation using proton magnetic resonance spectroscopy.

OBJECTIVES: (1) A biochemical investigation of the motor cortex in patients with incomplete spinal cord injury and normal control subjects using proton magnetic resonance spectroscopy (MRS). (2) To relate any altered biochemistry with the physiological changes in corticospinal function seen after spinal cord injury. METHODS: A group of six patients with incomplete spinal cord injury who showed good recovery of motor function were selected. The patients were compared with five healthy control subjects. Electromyographic (EMG) responses of thenar muscles to transcranial magnetic stimulation (TMS) of the motor cortex showed that inhibition of cortical output was weaker in the patients than the controls. Proton MRS data were collected from a plane at the level of the centrum semiovale. Two 4.5 cm3 voxels in the motor cortex and a third voxel in the ipsilateral occipital cortex were examined in the patients and control subjects. RESULTS: The mean level of N-acetylaspartate (NAA), expressed relative to the creatine (Cr) peak (NAA/Cr), was significantly increased in the motor cortex of the patients compared with their ipsilateral occipital cortex or either cortical area in the controls. No differences between patients and controls were seen for any of the other metabolite peaks (choline (Cho), glutamate/glutamine (Glx) or the aspartate component of NAA (AspNAA)) relative to Cr. Choline relative to Cr (Cho/Cr) was higher in the motor cortex of the control subjects than in their ipsilateral occipital cortex. This difference was not present in the patients. CONCLUSIONS: Raised NAA/Cr in the motor cortex of the patients probably results from increased NAA rather than a decrease in the more stable Cr. The possible relevance of a raised NAA/Cr ratio is discussed, particularly with regard to the changed corticospinal physiology and the functional recovery seen in the patients.

Adult↗
PubMed1998

Saccadic eye movements in families multiply affected with schizophrenia: the Maudsley Family Study.

OBJECTIVE: Family studies have shown that abnormalities of smooth pursuit eye movement are increased in the adult relatives of schizophrenic probands as well as in the probands themselves. More recently, an inability of schizophrenic subjects to inhibit reflexive saccades reliably has been shown. This study aimed to test the hypothesis that the latter dysfunction is part of the extended schizophrenia phenotype. METHOD: With the use of infrared oculography, measurements of reflexive saccades and antisaccades were undertaken in 29 probands with schizophrenia, 50 of their nonpsychotic first-degree relatives, and 38 unrelated healthy volunteers. RESULTS: Probands, relatives, and healthy subjects showed no overall differences in the generation of reflexive saccades. However, in the antisaccade task, probands showed more saccadic distractibility when they were required to inhibit reflexive saccades. Analysis of corrective saccades showed that this was not due to failed comprehension or motivation. Relatives of the probands with high saccadic distractibility showed a higher distractibility rate than relatives of the probands with normal distractibility. Across all subjects, females showed a higher rate of distractibility errors than males. CONCLUSIONS: The ability to suppress reflexive saccades is an objective neurocognitive measure that is impaired in schizophrenic patients and in a proportion of their biological relatives. This antisaccade abnormality may be a vulnerability marker in a subset of schizophrenic patients and their families.

Adult↗
PubMed1998

A comparison of a community mental health centre-based psychiatric service with one based in an outpatient department at the same hospital.

Referrals and response to referrals of two psychiatric services with similar catchment areas of the same hospital, one with a Community Mental Health Care (CMHC) centre and the other based at an outpatient department, were compared over a five-month period. While the service with a CMHC had an increased number of referrals, which may reflect the aims of the CMHC of making mental health services more accessible and less stigmatised, most referrals were from general practitioners and therefore likely to be appropriate. In spite of its increased workload, the time from referral to assessment for the CMHC-based service was significantly shorter than for the outpatient-based service.

Adolescent↗
PubMed1997

Abnormal cerebral phospholipid metabolism in dyslexia indicated by phosphorus-31 magnetic resonance spectroscopy.

It has recently been suggested that many of the features of dyslexia may be explicable in terms of an abnormality of membrane phospholipid metabolism. To investigate this we studied 12 dyslexic and 10 non-dyslexic adults using in vivo cerebral phosphorus-31 magnetic resonance spectroscopy (31P MRS), as the phosphomonoester (PME) and phosphodiester (PDE) peaks include indices of membrane phospholipid turnover. Spectral localization was achieved using four-dimensional chemical shift imaging methods. The PME peak area was significantly elevated in the dyslexic group, as evidenced by higher ratios of PME/total phosphorus (F = 9.5, p < 0.006), PME/beta NTP (F = 17.5, p < 0.001) and PME/PDE (F = 6.9, p < 0.02). No other spectral measurements differed significantly between the groups. These findings are consistent with the hypothesis that membrane phospholipid metabolism is abnormal in dyslexia. The PME peak is multicomponent, but predominantly consists of phosphoethanolamine (PE) and phosphocholine (PC), which are precursors of membrane phospholipids. Our finding of raised PME in dyslexia could therefore reflect reduced incorporation of phospholipids into cell membranes, although definitive interpretation must await further evidence.

Adult↗
PubMed1997

Effects of antipsychotic medication on electromyographic responses to transcranial magnetic stimulation of the motor cortex in schizophrenia.

OBJECTIVE: To assess the effect of antidopaminergic antipsychotic medication on the electromyographic (EMG) responses of thenar muscles to transcranial magnetic stimulation (TMS) of the motor cortex in schizophrenic patients. METHODS: A group of nine drug naive schizophrenic patients was compared with a group of nine schizophrenic patients established on neuroleptic medication. Surface EMG recordings were made from the thenar muscles while patients maintained a weak isometric voluntary contraction. TMS was applied using a 9 cm circular stimulating coil centred over the vertex. The EMG responses to up to 50 magnetic stimuli were rectified and averaged. RESULTS: There was no difference in threshold TMS strength for eliciting compound motor evoked potentials (cMEPs), or in their latency, in drug naive and medicated patients. In some patients the silent period (SP) was clearly made up of two parts and the percentage of control levels of voluntary EMG was measured in each component. During the early component of the SP there was a weaker (P<0.05) suppression of EMG in the medicated patients (mean 73.9 (SEM) 5.5% of control levels) compared with the drug naive patients (54.7 (SEM) 7.3% of control levels). This resulted in the latency of maximum suppression of voluntary EMG being longer (P<0.05) in the medicated patients (38.3 (2.4) ms) than in the drug naive patients (28.2 (0.7) ms). During the late component of the SP voluntary EMG was reduced to similar levels (P>0.05) in both medicated (48.2 (7.7)% of control levels) and drug naive (58 (7.8)% of control levels) patients. CONCLUSION: The results are discussed with reference to the disrupted inhibition seen in the early part of the SP in Parkinson's disease and drug induced parkinsonism. The future uses of motor responses to TMS as a marker for the status of antipsychotic medication are considered.

Adult↗
PubMed1997

An investigation into the practice and benefits of statutory aftercare in an inner city psychiatric service.

The implementation of statutory aftercare for psychiatric inpatients, as outlined in Section 117 of the Mental Health Act 1983 (England and Wales), was studied by examining current practice in an inner city psychiatric service. Seventy-seven per cent of patients received Section 117 aftercare; 56% of patients did not have an identified key worker. A significant proportion of those receiving statutory aftercare did not have evidence of adequate forward planning. General practitioners did not attend any meetings. Patients who had Section 117 aftercare were compared with those who did not. Using the Cox regression model, it was found there was no significant difference between these two groups in terms of time between discharge and first readmission, readmission rate, and length of first readmission.

Adolescent↗
PubMed1996

Elevated endogenous nitric oxide synthase inhibitor in schizophrenic plasma may reflect abnormalities in brain nitric oxide production.

Cellular origins of methylarginines are not precisely known but the presence of free methyl and dimethylarginines in the brain were reported. We have investigated the circulating concentrations of asymmetrical dimethylarginine NG,NG-dimethylarginine (ADMA), NG,NG-dimethylarginine (SDMA), nitrate and nitrite levels in drug naive first episode schizophrenic patients and matched control subjects. Three of those patients were treated with neurolepties for 3 months. Plasma ADMA levels increased significantly but nitrate levels were significantly low compared to control subjects. Drug treatment apparently lowered ADMA levels and increased nitrate levels in plasma. Methylation of arginine to methylarginines may have an important role in regulating signal transduction through the nitric oxide system in the brain, and suggest novel therapeutic targets.

Adult↗
PubMed1996

Abnormal saccadic distractibility in patients with schizophrenia: a 99mTc-HMPAO SPET study.

Recent research has shown that some patients with schizophrenia have a severe impairment in the suppression of reflexive saccadic eye movements in the ANTI-saccade task. This saccadic distractibility has previously been found in patients with lesions of dorsolateral prefrontal cortex, implicating an abnormality of prefrontal cortex. The objective of the present study was to determine the contribution of these and other areas to the ANTI-saccadic abnormality in schizophrenia by functional neuroimaging. Using 99mtechnetium-HMPAO high resolution multidetector single-photon emission tomography, regional cerebral blood flow (rCBF) during performance of the ANTI-saccade eye-movement task was compared, by statistical parametric mapping, in ten male schizophrenic patients on stable antipsychotic medication who had a high distractibility error rate on the task, and eight similar patients who had normal distractibility error rates. Compared with the normal error group, the patients with high error rates showed significantly decreased rCBF bilaterally, in the anterior cingulate, insula, and in left striatum. These same patients also had increased perseverative errors on the Wisconsin Card Sort Test.

Adult↗
PubMed1996

General practitioners' views of an open referral system to a community mental health service.

The satisfaction of general practitioners with a community mental health service operating an open referral system was compared to that with two services both operating a closed referral system covering the same inner-city district. The open referral system allows any agency (including patients) to contact the service by letter or by telephone, and priority is given to patients with serious mental illness. General practitioners' satisfaction with all aspects of the open referral system was greater than that with either of the closed referral systems. In particular, speed of assessment of referrals was preferred in the open referral system.

Community Mental Health Services↗
PubMed1996

Characteristics of young offenders detained under section 53(2) at a young offenders' institution.

The objective of the study was to investigate the medical and psychiatric characteristics and needs of detainees held under s.53(2) of the Children and Young Persons Act 1933. A case-note study of all subjects detained under s.53(2) at a young offenders' institution was carried out and their psychologists and medical officer interviewed. The subjects had a high risk of having experienced family disruption, of psychoactive substance abuse, and poor educational progress, and they were more likely than the general population to be Afro-Caribbean or of mixed race. They were psychologically vulnerable and could become suicidal when exposed to risk factors such as bullying and not being visited often by friends and relatives. However, there was a lack of information available about the subjects in many important areas including assessment of needs for special education, of truancy, expulsions, child guidance clinic attendance, and placement on child protection registers. It was not clear whether these young people had been significantly in contact with services as children or whether they had slipped through the net. In conclusion, the most important finding was a worrying lack of information about this group. From the information available they were clearly atypical. More research is needed; more adequate information, for example with respect to physical and sexual abuse, child rearing, education, peer relationships, and contact with specialist health and social services, would assist in the development of services for the treatment of these serious young offenders and for prevention.

Adolescent↗