Lewy body cortical involvement may not always predict dementia in Parkinson's disease

BACKGROUND

The presence of Lewy bodies (LB) in the neocortex and limbic system in patients with Parkinson's disease (PD) is commonly thought to be linked with cognitive impairment. The authors present here a series of patients with diagnosis of PD in life and no significant cognitive impairment who, at necropsy, satisfied the current neuropathological criteria for dementia with Lewy bodies (DLB).

METHODS

Two hundred and seventy six brains with PD pathology were examined at the Queen Square Brain Bank in London between 1993 and 1999. The neuropathological diagnosis was PD, but 117 patients also had sufficient LB involvement above the brain stem to satisfy the current neuropathological criteria for DLB (50 patients had a neuropathological picture consistent with the limbic category of DLB and 67 with neocortical DLB). Forty eight cases were excluded who developed early cognitive impairment together with motor features of parkinsonism, 12 cases for lack of detailed clinical history, and 19 cases with coexistent features of advanced Alzheimer's disease changes. Thirty eight patients (13.8% of the total with PD pathology and 32.5 % of the total with DLB pathology) were found where there was no or very late cognitive impairment reported in the clinical records.

RESULTS

Selected cases were 24 men and 14 women, with a mean (SD) age at onset of parkinsonian symptoms of 60.1 (10.1) years and a mean disease duration of 15.3 (5.5) years. At some time during the evolution of the disease 21 patients developed different degrees of cognitive impairment (after a mean disease duration of 12.2 (4.8) years). Clinical diagnosis at death was PD in 10 cases and PD with dementia in 11. In the remaining 17 patients no history of cognitive impairment was ever recorded in life and all of them had a clinical diagnosis of PD at death; in this subgroup, nine patients later revealed a neuropathological picture consistent with limbic (or transitional) category of DLB and eight with neocortical DLB. Interestingly, in all these patients the parkinsonian features including the response to dopaminergic drugs were indistinguishable from classic brain stem PD.

CONCLUSIONS

The authors demonstrate that the classic pathology of DLB can commonly be seen outside the generally accepted clinical spectrum for DLB and that important factors other than the absolute number of LB in the neocortex and limbic system influence the development of cognitive impairment in PD. Furthermore, the pathology of PD may be indistinguishable from that reported in DLB, suggesting that the two clinicopathological syndromes may be attributable to the same biological abnormality.

Parasitic worms of the central nervous system: an Australian perspective

The diagnosis and management of parasitic diseases of the central nervous system (CNS) is difficult, even for infectious diseases physicians and neurologists. Furthermore, few overviews of the spectrum of causative helminths and clinical syndromes have been published. In the present study, we review the seven most common parasitic diseases of the CNS: (i) cysticercosis, (ii) neuroschistosomiasis, (iii) paragonimiasis, (iv) angiostrongyliasis, (v) hydatid disease, (vi) sparganosis and (vii) gnathostomiasis. Major syndromes of parasitic disease of the CNS and their differential causes are discussed, including: (i) cystic lesions, (ii) enhancing granulomas (with and without creeping subcutaneous eruptions), (iii) eosinophilic meningoencephalitis and (iv) spinal cord disease. Specific risk factors that predispose to these infections are also discussed and particular attention is drawn to the situation in Australia.

Polymyositis as a cause of total gut failure

BACKGROUND

Gastrointestinal manifestations are seen in systemic sclerosis and mixed connective tissue disorders but are rare in pure polymyositis.

CASE REPORT

A 44 year old woman with polymyositis who developed total gut failure requiring treatment with total parenteral nutrition is described.

RESULTS

The patient's polymyositis is now fully controlled biochemically, but her gastrointestinal symptoms persist.

Improved accuracy of clinical diagnosis of Lewy body Parkinson's disease

The authors studied the accuracy of clinical diagnosis of idiopathic PD (IPD) in 100 consecutive clinically diagnosed cases that came to neuropathological examination. Ninety fulfilled pathologic criteria for IPD. Ten were misdiagnosed: multiple system atrophy (six), progressive supranuclear palsy (two), post-encephalitic parkinsonism (one), and vascular parkinsonism (one). Assessment of the clinical features suggests that an accuracy of 90% may be the highest that can be expected using current diagnostic criteria.

Motor imagery in Parkinson's disease: a PET study

We used positron emission tomography (PET) with 15O-labelled water to record patterns of cerebral activation in six patients with Parkinson's disease (PD), studied when clinically "off" and after turning "on" as a result of dopaminergic stimulation. They were asked to imagine a finger opposition movement performed with their right hand, externally paced at a rate of 1 Hz. Trials alternating between motor imagery and rest were measured. A pilot study of three age-matched controls was also performed. We chose the task as a robust method of activating the supplementary motor area (SMA), defects of which have been reported in PD. The PD patients showed normal degrees of activation of the SMA (proper) when both "off" and "on." Significant activation with imagining movement also occurred in the ipsilateral inferior parietal cortex (both "off" and when "on") and ipsilateral premotor cortex (when "off" only). The patients showed significantly greater activation of the rostral anterior cingulate and significantly less activation of the left lingual gyrus and precuneus when performing the task "on" compared with their performance when "off." PD patients when imagining movement and "off" showed less activation of several sites including the right dorsolateral prefrontal cortex (DLPFC) when compared to the controls performing the same task. No significant differences from controls were present when the patients imagined when "on." Our results are consistent with other studies showing deficits of pre-SMA function in PD with preserved function of the SMA proper. In addition to the areas of reduced activation (anterior cingulate, DLPFC), there were also sites of activation (ipsilateral premotor and inferior parietal cortex) previously reported as locations of compensatory overactivity for PD patients performing similar tasks. Both failure of activation and compensatory changes are likely to contribute to the motor deficit in PD.

Reduced BDNF mRNA expression in the Parkinson's disease substantia nigra

Brain-derived neurotrophic factor (BDNF) has potent effects on survival and morphology of dopaminergic neurons and thus its loss could contribute to death of these cells in Parkinson's disease (PD). In situ hybridization revealed that BDNF mRNA is strongly expressed by dopaminergic neurons in control substantia nigra pars compacta (SNpc). In clinically and neuropathologically typical PD, SNpc BDNF mRNA expression is reduced by 70% (P = 0.001). This reduction is due, in part, to loss of dopaminergic neurons which express BDNF. However, surviving dopaminergic neurons in the PD SNpc also expressed less BDNF mRNA (20%, P = 0.02) than their normal counterparts. Moreover, while 15% of control neurons had BDNF mRNA expression >1 SD below the control mean, twice as many (28%) of the surviving PD SNpc dopaminergic neurons had BDNF mRNA expression below this value. This 13% difference in proportions (95% CI 8-17%, P < or = 0.000001) indicates the presence of a subset of neurons in PD with particularly low BDNF mRNA expression. Moreover, both control and PD neurons displayed a direct relationship between the density of BDNF mRNA expression per square micrometer of cell surface and neuronal size (r(2) = 0.93, P </= 0.00001) which was lost only in PD neurons expressing the lowest levels of BDNF mRNA. If BDNF is an autocrine/paracrine factor for SNpc dopaminergic neurons, loss of BDNF-expressing neurons may compromise the well-being of their surviving neighbors. Moreover, neurons expressing particularly low levels of BDNF mRNA may be those at greatest risk of injury in PD and possibly the trigger for the degeneration itself.

New dopaminergic neurons in Parkinson's disease striatum

A new population of dopaminergic neurons has been identified in Parkinson's disease striatum. These neurons are sufficiently numerous to have an important effect on dopaminergic function in the striatum.

Voice characteristics in the progression of Parkinson's disease

This study examined the acoustic and perceptual voice characteristics of patients with Parkinson's disease according to disease severity. The perceptual and acoustic voice characteristics of 30 patients with early stage PD and 30 patients with later stage PD were compared with data from 30 normal control subjects. Voice recordings consisted of prolongation of the vowel /a/, scale singing, and a 1-min monologue. In comparison with controls and previously published normative data, both early and later stage PD patients' voices were characterized perceptually by limited pitch and loudness variability, breathiness, harshness and reduced loudness. High modal pitch levels also characterized the voices of males in both early and later stages of PD. Acoustically, the voices of both groups of PD patients demonstrated lower mean intensity levels and reduced maximum phonational frequency ranges in comparison with normative data. Although less clear, the present data also suggested that the PD patients' voices were characterized by excess jitter, a high-speaking fundamental frequency for males and a reduced fundamental frequency variability for females. While several of these voice features did not appear to deteriorate with disease progression (i.e. harshness, high modal pitch and speaking fundamental frequency in males, fundamental frequency variability in females, low intensity and jitter), breathiness, monopitch and monoloudness, low loudness and reduced maximum phonational frequency range were all worse in the later stages of PD. Tremor was the sole voice feature which was associated only with later stage PD.

Gait analysis in patients with Parkinson's disease and motor fluctuations: influence of levodopa and comparison with other measures of motor function

Although clinical rating scales and simple timed tests of motor function are widely used to assess motor response to therapy, gait analysis may provide an alternative measure of this response. We studied 15 patients with PD complicated by motor fluctuations, first to determine changes in temporal and spatial gait parameters following levodopa, secondly to assess the stability of repeated gait measures and timed tests in "off" and "on" states, and thirdly to determine the use of gait analysis in the assessment of the dopaminergic response. Gait analysis (velocity, stride length, cadence, and double limb support), clinical rating scales (modified Webster scale and Hoehn and Yahr stage), and timed tests of motor function (hand tapping and stand-walk-sit time) were performed before ("off") and after ("on") a levodopa challenge. Stride length and gait velocity increased following medication whereas cadence and double limb support did not. Most gait measures and the stand-walk-sit time were stable over three consecutive trials in both "off" and "on" states. Of the gait measures, only cadence in the "off" state changed significantly whereas the tapping count improved with repeated trials in both "off" and "on" states. Changes in stride length, gait velocity, and tapping count following levodopa correlated with changes in clinical rating scales following treatment. Measurement of gait parameters provides a reliable, objective alternative to rating scales and timed tests in assessing the dopaminergic response in patients with PD and motor fluctuations.

Hyperbaric oxygen in the treatment of refractory haemorrhagic cystitis

Haemorrhagic cystitis is a common and often debilitating complication of chemotherapy for which treatment is frequently unsatisfactory. With over 80 cases reported of radiation-induced cystitis treated successfully with hyperbaric oxygen, attention is now turning to the treatment of chemotherapeutic agent-induced cystitis. We report a case of haemorrhagic cystitis occurring after autologous peripheral blood stem cell transplantation for multiple myeloma. The patient had received cyclophosphamide and busulfan and had BK and adenoviruria. The haemorrhage was refractory to multiple conventional treatments but resolved after a course of hyperbaric oxygen.

Apomorphine-induced penile erections in Parkinson's disease

Penile erections were regularly induced by intermittent subcutaneous injections of apomorphine in five patients with Parkinson's disease (PD) complicated by motor fluctuations. Four of the patients reported erectile dysfunction before beginning apomorphine and two of these report a significant improvement in their sexual function resulting from apomorphine use. Animal studies suggest central D2-type dopamine receptor stimulation and oxytocin release from the paraventricular nucleus of the hypothalamus mediate the effect. Erections reported with other dopamine agonists and levodopa are probably mediated by the same mechanism. Apomorphine-induced erections in PD are probably more common than previously thought. The benefit of apomorphine on sexual function in some patients suggests a possible role in the treatment of impotence in PD.

Clinicopathological aspects of Parkinson's disease

Clinicopathological studies have shown that the accuracy of a clinical diagnosis of Parkinson's disease (PD) is less than 80%. More selected diagnostic criteria can increase the proportion of true PD cases identified to more than 90%. However, by using these criteria almost a third of pathologically confirmed cases may be rejected. Awareness of the high misdiagnosis rate and refinements in the clinical diagnostic criteria for other conditions that may present with parkinsonism seem to have led to an improvement in the accuracy of diagnosis to 84%. Cortical Lewy bodies, often in small numbers, are seen in almost all patients with PD. This has prompted intense efforts to clarify both the clinical and pathological criteria for diffuse Lewy body disease. The nomenclature of conditions with plentiful numbers of Lewy bodies in the neocortex and the relevance of associated pathology has become confusing and the subject of intense nosological debate. A recent consensus paper has suggested clinical and pathological diagnostic criteria for what has been termed 'dementia with Lewy bodies'. This new term awaits general acceptance while the proposed diagnostic criteria remain to be validated. The neuropathological substrate of dementia in PD continues to receive a lot of attention with suggestions that additive deficits from pathology in both cortical and subcortical structures probably explain most of the dementia seen in PD.

Response of parkinsonian swallowing dysfunction to dopaminergic stimulation

OBJECTIVES

To determine the degree of dopaminergic response of swallowing dysfunction in Parkinson's disease.

METHODS

Fifteen patients with idiopathic Parkinson's disease and symptomatic dysphagia were studied. All had motor fluctuations in response to long term levodopa therapy. On two separate days, after overnight withdrawal of all antiparkinsonian medication, a modified barium swallow using cinefluoroscopy and different food consistencies was performed before and after administration of oral levodopa and subcutaneous apomorphine.

RESULTS

Despite all patients having an unequivocal motor response to both agents, there were few significant responses in any of the quantitative or qualitative criteria of swallowing dysfunction assessed. The oral preparatory phase, generally considered a more voluntary component of swallowing, showed a response, but not with all consistencies. In a subgroup of patients the pharyngeal phase time also improved.

CONCLUSIONS

These findings suggest that parkinsonian swallowing dysfunction is not solely related to nigrostriatal dopamine deficiency and may be due to an additional non-dopamine related disturbance of the central pattern generator for swallowing in the pedunculopontine nucleus or related structures in the medulla.

Drug treatment of Parkinson's disease in the 1990s. Achievements and future possibilities

Advances in the medical treatment of Parkinson's disease have improved the disability related to complications of long term levodopa therapy, including motor fluctuations, dyskinesias and neuropsychiatric toxicity. A range of new dopamine agonists are in various stages of preclinical and clinical development. Cabergoline appears to be effective in improving moderate motor fluctuations, and a number of dopamine partial agonists that can act as either agonists or antagonists depending on the degree of denervation and receptor sensitivity are being investigated. Apomorphine represents a significant advance in the treatment of well developed motor fluctuations in selected patients who are able to master the technique of subcutaneous administration. The catecholamine-O-methyl transferase inhibitors are proving useful in phase III studies in the management of patients with moderate motor fluctuations. A role for glutamate antagonists is supported by animal and early clinical data, although the poor therapeutic index associated with the currently available nonselective, noncompetitive glutamate antagonists has prompted a search for more selective antagonists with less toxicity. The management of levodopa-induced dyskinesias remains a major therapeutic challenge. Some reports of dopamine partial agonists, selective D2 receptor antagonists and atypical antipsychotics being useful await confirmation. Neuropsychiatric toxicity probably remains the major dose-limiting adverse effect of levodopa and is a major reason for parkinsonian patients being admitted to nursing homes. The development of new atypical antipsychotics with improved therapeutic indices, along with the possible use of serotonergic antagonists, may improve management of this difficult problem. The challenge will be to fit these new forms of treatment into our present range of available drugs and to assess their relative role within the emerging framework of functional neurosurgery for parkinsonian disability.

Motor response to acute dopaminergic challenge with apomorphine and levodopa in Parkinson's disease: implications for the pathogenesis of the on-off phenomenon

OBJECTIVES

To evaluate the contribution of postsynaptic changes to motor fluctuations, three groups of parkinsonian patients with differing responses to treatment were acutely challenged with two dopaminergic drugs-apomorphine and levodopa-having different mechanisms of action.

METHODS

Forty two patients with Parkinson's disease (14 untreated, eight with a stable response to levodopa, and 20 with levodopa induced motor fluctuations) were challenged on two consecutive days with apomorphine and levodopa. The latency, duration, and magnitude of motor response was measured.

RESULTS

A progressive shortening of mean latency after levodopa challenge was found passing from the untreated to the stable and fluctuating groups; the difference between untreated and fluctuating patients was statistically significant (P < 0.01). Response duration after levodopa challenge was similar in untreated and stable patients, whereas it showed a significant shortening in patients with motor fluctuations (P < 0.05 v both untreated and stable patients). When subcutaneous apomorphine was given, untreated patients had a longer response duration than those who had developed motor fluctuations (P < 0.05). Although baseline disability was significantly greater in the fluctuating patients than in the untreated and stable patients, the severity of residual parkinsonian signs after both apomorphine and levodopa challenge was similar for all three groups; as a result, the degree of improvement in parkinsonian signs after dopaminergic stimulation was substantially greater in more advanced than in early cases. Linear regression analysis also indicated that latency and duration after apomorphine challenge did not significantly correlate with those after levodopa challenge, whereas magnitude of response to apomorphine showed a strong positive correlation with that after levodopa challenge (r = 0.9, P < 0.001).

CONCLUSION

The progressive shortening of motor response after both apomorphine and levodopa suggests that pharmacodynamic factors play an important part in determining the duration of motor response and argue against altered central pharmacokinetics of levodopa being principally responsible for the on-off effect. The widening response amplitude and increasing off phase disability occurring during disease progression are also critical factors in determining the appearance of motor fluctuations.

Detection and subcellular localization of an AML1 chimeric protein in the t(8;21) positive acute myeloid leukemia

AML1, a gene encoding a protein of the PEBP2/CBF family of transcription factors is disrupted by translocations associated with human leukemia. In the t(8;21) acute myelogenous leukemia (AML), AML1 was found fused to a gene on chromosome 8 that we designated CDR (also known as ETO and MTG8). Immunoprecipitation experiments followed by immunoblotting using a combination of antibodies against different epitopes of one of the predicted chimeric proteins encoded by a fully characterized fusion transcript enabled us to visualize a chimeric protein in the t(8;21) Kasumi-1 cell line. The estimated size of this protein is 64 kDa. Immunoblotting of leukemic blasts containing the t(8;21) detected a protein of the same size. Immunofluorescence experiments indicate that the chimeric protein is localized in the nucleus. A normal AML1 protein of 27 kDa was also detected in t(8;21) Kasumi-1 cells. It remains to be established by which mechanism the mutant AML1 isoform may contribute to the leukemogenesis process of t(8;21)-positive acute myeloid leukemia.