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Biomedical subjects

M Jahanshahi

Publications and source records attributed to M Jahanshahi.

At least 19 recordsLinked to original sources
PubMed1992

Rapid and efficient purification of cimetropium bromide and mifentidine drug metabolite mixtures derived from microsomal incubates for analysis by mass spectrometry.

A comparative study of the use of organic solvent extraction versus Sep-Pak C18 cartridges in the recovery and analysis of phase I (unconjugated) drug metabolites using mass spectrometry is presented. Standard mixtures of putative metabolites of the anticholinergic drug cimetropium bromide and the H2-antagonist mifentidine were purified from inactivated liver microsomal preparations using both methods, and subsequently the recovery of each compound was quantitated. In general, the percentage recovery and degree of purification were greater when using Sep-Pak C18 cartridges compared with organic solvent extraction. Even more efficient recovery was achieved when zinc sulphate precipitation of proteins in the liver microsomal mixtures was carried out prior to analysis. Also, the HPLC-grade solvents used in this study contained a variety of ultraviolet-inactive, hydrophobic components. This leads to problems of suppression in fast atom bombardment mass spectrometric analysis. Using Sep-Pak C18 cartridges directly prior to analysis by fast atom bombardment with single or tandem mass spectrometry leads to far superior mass spectral results compared with organic solvent extraction.

Androgen Antagonists↗
PubMed1992

Time estimation and reproduction is abnormal in Parkinson's disease.

We compared the performance of 44 patients with Parkinson's disease (PD), tested 12-24 h after withdrawal of dopaminergic medication, with 20 age-matched controls, on a verbal test for time estimation and in several time reproduction tasks. Patients with PD underestimated the duration of a time interval in the verbal time estimation task and showed overproduction of time intervals when required to reproduce a short time sample. Absolute errors were greater in the reproduction of longer time intervals in both control and PD patients, but especially in the latter. The presentation of time markers at faster rates had a detrimental effect on the performance of the patients but not of the controls. Patients with more severe PD performed worse on the time estimation and reproduction tasks compared with those with milder disease. Administration of levodopa-carbidopa (205/25 mg, p.o.) significantly reduced absolute errors in time estimation and reproduction in conditions where time markers were presented at the two faster rates of 5 Hz and 3.3 Hz. Performance in these two latter tests best discriminated patients and controls and had a positive significant association with simple reaction time and movement time. These results lead us to suggest that time estimation, i.e. the 'internal clock', is abnormally slow in PD.

Adult↗
PubMed1992

Simple and choice reaction time and the use of advance information for motor preparation in Parkinson's disease.

The effects of different types of advance information (warning signal, temporal cue, movement parameter cue), presented at different intervals before an imperative stimulus on reaction time (RT) were examined. Sixteen patients with Parkinson's disease and 16 age-matched normal controls performed a simple reaction time (SRT) task, an uncued, two partially cued (cueing of direction of movement or hand) and a fully cued visual four choice reaction time (CRT) tasks. An S1-S2 paradigm was used, where a warning signal/precue (S1) preceded the imperative signal (S2) by 0 (uncued and unwarned conditions), 200 ms, 800 ms, 1600 ms or 3200 ms. When the unwarned SRT and uncued CRT conditions were compared, the patients were slower than the controls in both conditions, with the group differences being larger for the CRT than the SRT task. Both patients and controls benefited from a warning signal presented before the imperative stimulus (S2), especially when it occurred 200 ms prior to S2. Advance information about the parameters of the required response was used by both patients and controls to preprogramme responses before the onset of S2. In both groups, RTs were generally faster for longer S1-S2 intervals. With an S1-S2 interval of 3200 ms, advance information about two movement parameters was 'fully' used by the patients to preprogramme responses such that their fully cued CRT was reduced to the level of SRT. In the controls, this process was complete by 800 ms. The most parsimonious explanation of the pattern of results across the SRT, fully cued CRT and uncued CRT conditions would be in terms of a slowness in response initiation in Parkinson's disease, which is a stage of processing common to all RT conditions. Deficits at one or more of the stages of processing unique to CRT are, however, necessary to explain the differentially greater slowness of uncued CRT in Parkinson's disease.

Aged↗
PubMed1992

Performance of repetitive wrist movements in Parkinson's disease.

The timing of repetitive alternating 80 degrees flexion-extension movements of the right wrist was studied in 42 patients with Parkinson's disease, tested while not receiving dompaminergic medication and 20 age- and sex-matched controls. Five rates of movement (0.5 Hz, 1 Hz, 1.5 Hz, 2 Hz, 2.5 Hz) were examined. The interval between two successive flexion movements, as measured from the electromyography (EMG) records was taken as the unit of analysis or inter-response interval (IRI). At 0.5 Hz, 1 Hz and 1.5 Hz there were no differences between groups in mean IRIs. At higher rates of movement (2 Hz and 2.5 Hz), however, the controls were significantly more accurate in timing of repetitive movements than the patients. At all five frequencies, the patients with moderate or severe Parkinson's disease were less accurate in timing of repetitive movements than those with mild disease, although the differences were not significant. In nine patients tested in the 'on' and 'off' medication states, administration of 250 mg of levodopa/carbidopa resulted in significantly more accurate timing of repetitive movements. Wing and Kristofferson's (1973b) two-process model of repetitive movements was applied to the IRI data. At various rates of movement, the primary prediction of the model that lag 1 autocorrelations should be in the 0 to -0.5 range was violated in 40-70% of the patient and controls. For those subjects who had lag 1 autocorrelations in the expected range, IRI variability was to break down into a timekeeper and a motor delay variance. At all frequencies, the patients had significantly higher variance for IRI, timekeeper and motor delay than the controls. Although not significant, more severe Parkinson's disease was associated with greater IRI, timekeeper and motor delay variance, while administration of levodopa resulted in reduction of the three types of variance. The validity of the Wing and Kristofferson model for the analysis of this type of movement is discussed.

Acoustic Stimulation↗
PubMed1992

The effect of withdrawal of dopaminergic medication on simple and choice reaction time and the use of advance information in Parkinson's disease.

Eight patients with Parkinson's disease performed simple reaction time (SRT), uncued, partially and fully cued four choice (CRT) tasks. They were tested on two occasions; on their normal dose of dopaminergic medication and following withdrawal of such medication for an average of 14.4 hours. Disability as rated on the Webster scale was greater in the drug reduced state. Although RTs were generally slower when tested in the drug reduced state than when on medication, few differences emerged. Withdrawal of dopaminergic medication had no effect on unwarned SRT and unwarned and uncued CRT performance. Both on and off medication, the patients benefited from a warning signal presented before the imperative stimulus. In both medication states, the speeding up of RT was greatest with a warning signal presented 200 ms before S2. When the imperative stimulus was unwarned, the temporal predictability of its occurrence speeded RT more when on medication than when off. Advance movement parameter information was used by patients to pre-programme responses both on and off medication. In both medication states, the fully cued CRT was the same as SRT only with the 3200 ms S1-S2 interval. Medication state had no effect on movement time or the number of errors. It is suggested that slowness in motor readiness and motor programming may not be specific to striatal dopamine deficiency but rather a nonspecific concomitant of brain damage.

Adult↗
PubMed1992

Psychological functioning before and after treatment of torticollis with botulinum toxin.

The impact of botulinum toxin injection on psychological function was assessed in 26 patients with idiopathic torticollis. Eighty five per cent of the patients and 88% of the relatives considered torticollis to be better following the injections. Symptomatic improvement with the injections was associated with significant reduction of depression and disability, but non-significant improvement in body concept, and self-esteem. This concordant pattern of change in symptoms and psychological function with the injections supports the proposal that in torticollis depression and disability are consequences of the postural abnormality of the head.

Adult↗
PubMed1992

Effect of practice on performance of a skilled motor task in patients with Parkinson's disease.

Parkinson's disease leads to a breakdown in the execution of highly practised, skilled movements such as walking and handwriting. The improved execution of skilled movements with practice can be understood as a process of schema learning, the determining of the relevant parameters of the specific movement. The ability of patients with Parkinson's disease and age matched normal control subjects to improve their performance, with practice, on a skilled motor task, doing up buttons, was assessed. The task was assessed on its own and with simultaneous foot tapping. Both groups showed an initial improvement in the task on its own and deterioration in performance when buttoning with foot tapping. The amount of interference, however, decreased with practice, particularly in the patients with a 2 Hz tapping rate. The results suggest that patients with Parkinson's disease are capable of schema learning but require more practice than control subjects to achieve comparable levels of performance. This may be a reflection of the fundamental motor dysfunction of the disease rather than a specific learning deficit.

Adult↗
PubMed1992

Bioanalytical applications of tandem mass spectrometry in the in vitro metabolism of the anticholinergic drug cimetropium bromide to detect differences in species metabolism.

1. In vitro metabolism of the anticholinergic drug, cimetropium bromide, was investigated using four different animal hepatic microsomal incubates derived from rat, hamster, guinea pig, and mouse livers. 2. Constant neutral loss (CNL) tandem mass spectrometry was used to detect the presence of the N-methylenecyclopropyl-scopine functionality by monitoring loss of 54 daltons (corresponding to loss of methylenecyclopropane) in microsomal incubates. 3. A CNL loss of 46 daltons was used to screen for the presence of ester hydrolysis products. 4. A comparison of the daughter ion spectra obtained on ions detected by CNL scanning, with daughter ion spectra of synthetic standards, determined the presence of ten metabolites of cimetropium bromide. 5. Hydroxylation of the aromatic ring in the ester side-chain was found to be the major metabolic pathway, and ester bond hydrolysis was a minor metabolic pathway. 6. N-Demethylation of the bridgehead nitrogen was observed only in rat and hamster incubates. 7. Using the method of CNL scanning it was possible to screen different animal microsomal incubates without resorting to any major purification procedures such as h.p.l.c. 8. This scanning method revealed differences between species in the metabolic pathways of cimetropium bromide.

Animals↗
PubMed1991

EMG biofeedback treatment of torticollis: a controlled outcome study.

Successful treatment of torticollis with electromyographic (EMG) biofeedback has been reported in a number of single case and single group studies. The present investigation represents the first controlled outcome study. Twelve torticollis patients were randomly assigned to EMG biofeedback or relaxation training and graded neck exercises (RGP). The procedure involved three sessions of baseline assessment, 15 sessions of EMG BF or RGP, 6 sessions of EMG BF or RGP plus home-management, 6 sessions of home-management alone, and follow-up 3 months after the end of treatment. A variety of outcome measures were used including physiological (EMG from the two sternocleidomastoid muscles, skin conductance level), behavioral (angle of head deviation, range of movement of the head), and self-report (depression, functional disability, body concept), therapist and "significant other" reports and independent observer assessment of videos. In both groups, neck muscle activity was reduced from pre- to posttreatment. This reduction was greater in the EMG biofeedback group. There was evidence of feedback-specific neck muscle relaxation in the EMG biofeedback group. Therefore, the outcome was not due to nonspecific factors and could be attributed to feedback-specific effects. Changes in skin conductance level showed that neck muscle relaxation was not simply mediated by a general reduction of "arousal." Significant improvements of extent of head deviation, and range of movement of the head, as well as reductions of depression were present, which were not different in the two groups. At the end of treatment, no patient was asymptomatic. Any therapeutic benefit was generally maintained at follow-up. The results and the procedural simplicity of RGP make the issue of cost-efficacy of EMG biofeedback a pertinent one. Further controlled outcome studies of EMG biofeedback treatment of torticollis with larger samples are required.

Adult↗
PubMed1991

Psychosocial factors and depression in torticollis.

Sixty-seven patients suffering from spasmodic torticollis, a neurological disorder in which involuntary contractions of the head produce an abnormal head posture, completed a booklet of questionnaires aiming to assess psychosocial adjustment. Twenty-four per cent of the patients were moderately to severely depressed. Overall, as a sample the patients were not acceptant of or adjusted to their illness. Cognitive and emotion-focused strategies were slightly more widely used than instrumental ways of coping. Both adaptive and maladaptive coping strategies were more frequently used by female than male sufferers. The number of individuals who were potential sources of social support was not high (mean = 2.7, SD = 1.2). The patients were, however, generally satisfied with the available support. Self-depreciation, lack of control over head position/movement and the resulting disability in activities of daily living, lack of satisfaction with available social support, and the use of maladaptive coping strategies accounted for 75% of the variance of depression in torticollis. Self-depreciation, which was the most salient predictor of depression in torticollis, accounting for 59% of its variance, was itself shown to arise from the patient's negative body concept relating to the postural abnormality of the head. As the severity of illness and resulting disability contributed to depression, successful symptomatic treatment of torticollis would be expected to ameliorate mood. However, as the currently available medical treatments are not effective for all treated cases, and as the self-depreciation resulting from a negative body concept formed the core of depression in torticollis, cognitive-behavioural therapy could improve the quality of life of the depressed torticollis patient.

Adaptation, Psychological↗
PubMed1990

Natural history of adult-onset idiopathic torticollis.

The rates of spontaneous remission and progression of dystonia to other sites were studied in 72 patients who first presented with adult-onset torticollis, and who were followed up for a mean of 7.7 years. Dystonia had progressed to sites other than the neck (mainly the face and upper limbs) in 23 patients (32%). The latter cases were not differentiated from those with isolated torticollis in terms of any of the demographic or clinical features studied, although they tended to have suffered from torticollis longer. Fifteen patients (20.8%) had experienced a spontaneous remission of their torticollis, which was sustained for a median period of 3 years in 9 cases (12.5%). Eighty-seven percent of the 15 remissions had occurred during the first 5 years of the illness. In the 9 cases with sustained remission, the duration of torticollis before spontaneous remission was significantly longer and remission had mostly occurred after 2 years of illness compared with the 6 who had relapsed. The 15 cases with spontaneous remission tended to have an earlier age of onset compared with those with no remission. Sixty-five percent of cases were correctly classified on the basis of age at onset, which emerged as the only salient variable in the discrimination of the 15 patients with spontaneous remission from the 57 without spontaneous remission. Age at onset, form of torticollis, gender, and direction of head deviation resulted in a correct classification rate of 70%, in the discrimination of the 9 cases with sustained remission from those with no remission.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Sexual function in patients with Parkinson's disease and their partners.

Sexual function in patients with Parkinson's disease has received virtually no attention. There are many reasons (physical, psychological and social), why such patients might experience problems within their sexual relationships. A group of patients and their partners completed a series of self-report measures, aimed at assessing sexual function and a range of factors which might be associated with any difficulties. The results revealed a high level of dysfunction, not just in the patients but also in their partners. Most effected were the couples in which the patient was male. A range of problems were reported by both patients and their partners. These were, in turn, associated with a range of variables relating to the disease, psychological and social factors. No simple causal model was suggested, and a multimodal therapeutic approach might be expected to have most benefit.

Activities of Daily Living↗
PubMed1989

Accuracy of self-reported disability in patients with parkinsonism.

For the patient, the most important aspect of parkinsonism is the degree to which the disease interferes with daily living. The patient's self-report may be the only way in which such information can be obtained. Depression and cognitive impairment, however, may influence that self-report. In the present study, three ratings of disability, from the patient, a relative, and an independent observer, showed high levels of agreement. The patients' cognitive function made a small but significant contribution to the accuracy of their self-report judged against the relative's rating. Depression, however, played no role. Agreement between patients and relatives for individual items on the disability questionnaire was reasonably high. The results suggest that patients with parkinsonism can provide accurate self-report of their level of disability, even in the presence of depression and cognitive impairment.

Activities of Daily Living↗
PubMed1989

Pain avoidance in rheumatoid arthritis.

Forty-eight patients with rheumatoid arthritis were compared to 52 pain-free controls in terms of tolerance/avoidance and rated intensity of cold pressor pain. The patients had lower thresholds and tolerated the cold pressor pain for a shorter period, although not significantly so. However, the patients rated the novel nociceptive cold stimulus as significantly more painful. The results demonstrate that arthritis patients report novel pain experiences as being more painful, which necessitates special attention to their post-operative analgesic demands needs. Tolerance/avoidance of the cold pressor pain had different correlates in the more and less chronic patient groups, and was respectively related to the affective and sensory qualities of the pain stimulus. The results confirmed qualitative similarities between different chronic pain populations, suggesting that chronicity of the pain problem may be a more important factor in determining pain experience and pain-related behaviours than the specific locus of the pain.

Adult↗
PubMed1988

Personality in torticollis: a controlled study.

The Eysenck Personality Questionnaire, the trait scales of the Leyton Obsessional Inventory, the Spielberger State Trait Anxiety Inventory, and a questionnaire assessing marital status and harmony were completed by 100 torticollis patients and a control group of 49 cervical spondylosis sufferers. Information regarding employment status, and events preceding onset of their complaint was also obtained. The two groups did not differ in terms of any of the personality dimensions evaluated, or in their self-reports of events prior to onset of their illness. The groups differed significantly with regards to marital status (a higher proportion of the torticollis patients were single) but not marital harmony. A significantly higher proportion of the torticollis patients were in the permanently sick category of employment status. Findings of previous studies evaluating personality in torticollis and in sufferers of other disabling physical conditions are considered, and the results are discussed in terms of the effects of disabling chronic physical disorders.

Cervical Vertebrae↗
PubMed1988

Depression in torticollis: a controlled study.

Eighty-five patients with idiopathic, persistent spasmodic torticollis were compared to a control group of 49 patients with cervical spondylosis to assess (1) the prevalence of psychiatric disorder prior to and following the onset of their physical complaint, and (2) to establish the effect of torticollis on self-reports of depression on the Beck Depression Inventory, and self-rated hopelessness on the Hopelessness Scale. The prevalence of psychiatric disorder in the two groups did not differ. The torticollis patients had significantly higher mean scores on the Beck Depression Inventory, but did not differ from the control group in terms of hopelessness. Self-referent negative cognitions such as self-blame, self-accusation, self-punitive thoughts, and negative body-image emerged as the prominent component of depression in torticollis, which has implications for the management of depression in torticollis.

Adolescent↗