Structural underpinnings and long-term effects of resilience in Parkinson's disease

Resilience in neuroscience generally refers to an individual's capacity to counteract the adverse effects of a neuropathological condition. While resilience mechanisms in Alzheimer's disease are well-investigated, knowledge regarding its quantification, neurobiological underpinnings, network adaptations, and long-term effects in Parkinson's disease is limited. Our study involved 151 Parkinson's patients from the Parkinson's Progression Marker Initiative Database with available Magnetic Resonance Imaging, Dopamine Transporter Single-Photon Emission Computed Tomography scans, and clinical information. We used an improved prediction model linking neuropathology to symptom severity to estimate individual resilience levels. Higher resilience levels were associated with a more active lifestyle, increased grey matter volume in motor-associated regions, a distinct structural connectivity network and maintenance of relative motor functioning for up to a decade. Overall, the results indicate that relative maintenance of motor function in Parkinson's patients may be associated with greater neuronal substrate, allowing higher tolerance against neurodegenerative processes through dynamic network restructuring.

Motivational and cognitive predictors of apathy after subthalamic nucleus stimulation in Parkinson's disease

Postoperative apathy is a frequent symptom in Parkinson's disease patients who have undergone bilateral deep brain stimulation of the subthalamic nucleus. Two main hypotheses for postoperative apathy have been suggested: (i) dopaminergic withdrawal syndrome relative to postoperative dopaminergic drug tapering; and (ii) direct effect of chronic stimulation of the subthalamic nucleus. The primary objective of our study was to describe preoperative and 1-year postoperative apathy in Parkinson's disease patients who underwent chronic bilateral deep brain stimulation of the subthalamic nucleus. We also aimed to identify factors associated with 1-year postoperative apathy considering: (i) preoperative clinical phenotype; (ii) dopaminergic drug management; and (iii) volume of tissue activated within the subthalamic nucleus and the surrounding structures. We investigated a prospective clinical cohort of 367 patients before and 1 year after chronic bilateral deep brain stimulation of the subthalamic nucleus. We assessed apathy using the Lille Apathy Rating Scale and carried out a systematic evaluation of motor, cognitive and behavioural signs. We modelled the volume of tissue activated in 161 patients using the Lead-DBS toolbox and analysed overlaps within motor, cognitive and limbic parts of the subthalamic nucleus. Of the 367 patients, 94 (25.6%) exhibited 1-year postoperative apathy: 67 (18.2%) with 'de novo apathy' and 27 (7.4%) with 'sustained apathy'. We observed disappearance of preoperative apathy in 22 (6.0%) patients, who were classified as having 'reversed apathy'. Lastly, 251 (68.4%) patients had neither preoperative nor postoperative apathy and were classified as having 'no apathy'. We identified preoperative apathy score [odds ratio (OR) 1.16; 95% confidence interval (CI) 1.10, 1.22; P < 0.001], preoperative episodic memory free recall score (OR 0.93; 95% CI 0.88, 0.97; P = 0.003) and 1-year postoperative motor responsiveness (OR 0.98; 95% CI 0.96, 0.99; P = 0.009) as the main factors associated with postoperative apathy. We showed that neither dopaminergic dose reduction nor subthalamic stimulation were associated with postoperative apathy. Patients with 'sustained apathy' had poorer preoperative fronto-striatal cognitive status and a higher preoperative action initiation apathy subscore. In these patients, apathy score and cognitive status worsened postoperatively despite significantly lower reduction in dopamine agonists (P = 0.023), suggesting cognitive dopa-resistant apathy. Patients with 'reversed apathy' benefited from the psychostimulant effect of chronic stimulation of the limbic part of the left subthalamic nucleus (P = 0.043), suggesting motivational apathy. Our results highlight the need for careful preoperative assessment of motivational and cognitive components of apathy as well as executive functions in order to better prevent or manage postoperative apathy.

Impulsive-compulsive behaviour in early Parkinson's disease is determined by apathy and dopamine receptor D3 polymorphism

Impulsive-compulsive behaviour (ICB) is a frequently observed non-motor symptom in early Parkinson's disease after initiating dopamine replacement therapy. At the opposite end of the motivated behaviour spectrum, apathy occurs in early Parkinson's disease even before dopamine replacement is started. The co-occurrence of these behavioural conditions in Parkinson's disease raises questions about their relationship and underlying pathophysiological determinants. In previous imaging or genetic studies, both conditions have been associated with the limbic dopaminergic system. The risk variant of the Ser9Gly polymorphism of the dopamine receptor D3 (DRD3) is linked to increased dopamine affinity in the limbic striatum. With this in mind, we investigated how ICB expression is explained by apathy and DRD3 polymorphisms and their effects on grey matter volume and dopamine synthesis capacity. Fifty-four patients with early Parkinson's disease took part in anatomical T1-weighted MRI. Forty of them also underwent dynamic PET imaging using [18F]DOPA to measure striatal dopamine synthesis capacity. Further, Ser9Gly (rs6280) gene polymorphism influencing the DRD3 dopamine-binding affinity was determined in all patients. The severity of impulsive-compulsive behaviour and apathy was assessed using the Questionnaire for Impulsive-Compulsive Disorders Rating Scale and the Apathy Evaluation Scale. ICB and the severity of apathy were indeed positively correlated. Apathy and the DRD3 polymorphism were interactive risk factors for ICB severity. Apathy was significantly linked to atrophy of the bilateral putamen. Patients with the DRD3 risk type had reduced dopamine synthesis capacity in the putamen and limbic striatum, apathy was associated with reduced dopamine synthesis capacity in the limbic striatum. The results of [18F]DOPA reached only trend significance. Apathy in drug-naïve PD patients might be a consequence of impaired striatal dopaminergic tone. This may represent a predisposing factor for the development of ICB after the initiation of dopamine replacement therapy. The risk type of DRD3 could further amplify this predisposition due to its higher affinity to dopamine.

Efficacy and safety of clonidine for the treatment of impulse control disorder in Parkinson's disease: a multicenter, parallel, randomised, double-blind, Phase 2b Clinical trial

BACKGROUND

Impulse control disorders (ICDs) are frequently encountered in Parkinson's disease (PD).

OBJECTIVES

We aimed to assess whether clonidine, an α2-adrenergic receptor agonist, would improve ICDs.

METHODS

We conducted a multicentre trial in five movement disorder departments. Patients with PD and ICDs (n = 41) were enrolled in an 8-week, randomised (1:1), double-blind, placebo-controlled study of clonidine (75 μg twice a day). Randomisation and allocation to the trial group were carried out by a central computer system. The primary outcome was the change at 8 weeks in symptom severity using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) score. A reduction of the most elevated subscore of the QUIP-RS of more than 3 points without any increase in the other QUIP-RS dimension defined success.

RESULTS

Between 15 May 2019 and 10 September 2021, 19 patients in the clonidine group and 20 patients in the placebo group were enrolled. The proportion difference of success in reducing QUIP-RS at 8 weeks, was 7% (one-sided upper 90% CI 27%) with 42.1% of success in the clonidine group and 35.0% in the placebo group. Compared to patients in the placebo group, patients in the clonidine group experienced a greater reduction in the total QUIP-RS score at 8 weeks (11.0 points vs. 3.6).

DISCUSSION

Clonidine was well tolerated but our study was not enough powerful to demonstrate significant superiority compared to placebo in reducing ICDs despite a greater reduction of total QUIP score at 8 weeks. A phase 3 study should be conducted.

TRIAL REGISTRATION

The study was registered (NCT03552068) on clinicaltrials.gov on June 11, 2018.

Molecular Imaging in Parkinsonian Disorders—What’s New and Hot?

Highlights

Abstract

Neurodegenerative parkinsonian disorders are characterized by a great diversity of clinical symptoms and underlying neuropathology, yet differential diagnosis during lifetime remains probabilistic. Molecular imaging is a powerful method to detect pathological changes in vivo on a cellular and molecular level with high specificity. Thereby, molecular imaging enables to investigate functional changes and pathological hallmarks in neurodegenerative disorders, thus allowing to better differentiate between different forms of degenerative parkinsonism, improve the accuracy of the clinical diagnosis and disentangle the pathophysiology of disease-related symptoms. The past decade led to significant progress in the field of molecular imaging, including the development of multiple new and promising radioactive tracers for single photon emission computed tomography (SPECT) and positron emission tomography (PET) as well as novel analytical methods. Here, we review the most recent advances in molecular imaging for the diagnosis, prognosis, and mechanistic understanding of parkinsonian disorders. First, advances in imaging of neurotransmission abnormalities, metabolism, synaptic density, inflammation, and pathological protein aggregation are reviewed, highlighting our renewed understanding regarding the multiplicity of neurodegenerative processes involved in parkinsonian disorders. Consequently, we review the role of molecular imaging in the context of disease-modifying interventions to follow neurodegeneration, ensure stratification, and target engagement in clinical trials.

Limbic stimulation drives mania in STN-DBS in Parkinson disease: a prospective study

In this one-year prospective study, Parkinson's disease (PD) patients with or without mania following STN-DBS were compared to investigate risk and etiological factors, clinical management and consequences. Eighteen (16.2%) out of 111 consecutive PD patients developed mania, of whom 17 were males. No preoperative risk factor was identified. Postoperative mania was related to ventral limbic subthalamic stimulation in 15 (83%) patients, and resolved as stimulation was relocated to the sensorimotor STN, besides discontinuation or reduction of dopamine agonists and use of low-dose clozapine in 12 patients, while motor and nonmotor outcomes were similar. These findings underpin the prominent role of limbic subthalamic stimulation in postoperative mania. This article is protected by copyright. All rights reserved.

Depression in Patients with Parkinson's Disease: Current Understanding of its Neurobiology and Implications for Treatment

Depression is one of the most frequent and burdensome non-motor symptoms in Parkinson’s disease (PD), across all stages. Even when its severity is mild, PD depression has a great impact on quality of life for these patients and their caregivers. Accordingly, accurate diagnosis, supported by validated scales, identification of risk factors, and recognition of motor and non-motor symptoms comorbid to depression are critical to understanding the neurobiology of depression, which in turn determines the effectiveness of dopaminergic drugs, antidepressants and non-pharmacological interventions. Recent advances using in vivo functional and structural imaging demonstrate that PD depression is underpinned by dysfunction of limbic networks and monoaminergic systems, depending on the stage of PD and its associated symptoms, including apathy, anxiety, rapid eye movement sleep behavior disorder (RBD), cognitive impairment and dementia. In particular, the evolution of serotonergic, noradrenergic, and dopaminergic dysfunction and abnormalities of limbic circuits across time, involving the anterior cingulate and orbitofrontal cortices, amygdala, thalamus and ventral striatum, help to delineate the variable expression of depression in patients with prodromal, early and advanced PD. Evidence is accumulating to support the use of dual serotonin and noradrenaline reuptake inhibitors (desipramine, nortriptyline, venlafaxine) in patients with PD and moderate to severe depression, while selective serotonin reuptake inhibitors, repetitive transcranial magnetic stimulation and cognitive behavioral therapy may also be considered. In all patients, recent findings advocate that optimization of dopamine replacement therapy and evaluation of deep brain stimulation of the subthalamic nucleus to improve motor symptoms represents an important first step, in addition to physical activity. Overall, this review indicates that increasing understanding of neurobiological changes help to implement a roadmap of tailored interventions for patients with PD and depression, depending on the stage and comorbid symptoms underlying PD subtypes and their prognosis.

Limbic Serotonergic Plasticity Contributes to the Compensation of Apathy in Early Parkinson's Disease

BACKGROUND

De novo Parkinson's disease (PD) patients with apathy exhibit prominent limbic serotonergic dysfunction and microstructural disarray. Whether this distinctive lesion profile at diagnosis entails different prognosis remains unknown.

OBJECTIVES

To investigate the progression of dopaminergic and serotonergic dysfunction and their relation to motor and nonmotor impairment in PD patients with or without apathy at diagnosis.

METHODS

Thirteen de novo apathetic and 13 nonapathetic PD patients were recruited in a longitudinal double-tracer positron emission tomography cohort study. We quantified the progression of presynaptic dopaminergic and serotonergic pathology using [¹¹ C]PE2I for dopamine transporter and [¹¹ C]DASB for serotonin transporter at baseline and 3 to 5 years later, using linear mixed-effect models and mediation analysis to compare the longitudinal evolution between groups for clinical impairment and region-of-interest-based analysis.

RESULTS

After the initiation of dopamine replacement therapy, apathy, depression, and anxiety improved at follow-up in patients with apathy at diagnosis (n = 10) to the level of patients without apathy (n = 11). Patients had similar progression of motor impairment, whereas mild impulsive behaviors developed in both groups. Striato-pallidal and mesocorticolimbic presynaptic dopaminergic loss progressed similarly in both groups, as did serotonergic pathology in the putamen, caudate nucleus, and pallidum. Contrastingly, serotonergic innervation selectively increased in the ventral striatum and anterior cingulate cortex in apathetic patients, contributing to the reversal of apathy besides dopamine replacement therapy.

CONCLUSION

Patients suffering from apathy at diagnosis exhibit compensatory changes in limbic serotonergic innervation within 5 years of diagnosis, with promising evidence that serotonergic plasticity contributes to the reversal of apathy. The relationship between serotonergic plasticity and dopaminergic treatments warrants further longitudinal investigations. © 2022 International Parkinson and Movement Disorder Society.

Serotonergic and Dopaminergic Lesions Underlying Parkinsonian Neuropsychiatric Signs

BACKGROUND

Parkinson's disease (PD) is characterized by heterogeneous motor and nonmotor manifestations related to alterations in monoaminergic neurotransmission systems. Nevertheless, the characterization of concomitant dopaminergic and serotonergic dysfunction after different durations of Parkinson's disease, as well as their respective involvement in the expression and severity of neuropsychiatric signs, has gained little attention so far.

METHODS

To fill this gap, we conducted a cross-sectional study combining clinical and dual-tracer positron emission tomography (PET) neuroimaging approaches, using radioligands of dopamine ([¹¹ C]-N-(3-iodoprop-2E-enyl)-2-beta-carbomethoxy-3-beta-(4-methylphenyl)-nortropane) ([¹¹ C]PE2I) and serotonin ([¹¹ C]-N,N-dimethyl-2-(-2-amino-4-cyanophenylthio)-benzylamine) ([¹¹ C]DASB) reuptake, after different durations of Parkinson's disease (ie, in short-disease duration drug-naive de novo (n = 27, 0-2 years-duration), suffering from apathy (n = 14) or not (n = 13); intermediate-disease duration (n = 15, 4-7 years-duration) and long-disease duration, non-demented (n = 15, 8-10 years-duration) patients). Fifteen age-matched healthy subjects were also enrolled.

RESULTS

The main findings are threefold: (1) both dopaminergic and serotonergic lesions worsen with the duration of Parkinson's disease, spreading from midbrain/subcortical to cortical regions; (2) the presence of apathy at PD onset is associated with more severe cortical and subcortical serotonergic and dopaminergic disruption, similar to the denervation pattern observed in intermediate-disease duration patients; and (3) the severity of parkinsonian apathy, depression, and trait-anxiety appears primarily related to serotonergic alteration within corticostriatal limbic areas.

CONCLUSIONS

Altogether, these findings highlight the prominent role of serotonergic degeneration in the expression of several neuropsychiatric symptoms occurring after different durations of Parkinson's disease. © 2021 International Parkinson and Movement Disorder Society.

Early limbic microstructural alterations in apathy and depression in de novo Parkinson's disease

BACKGROUND

Whether structural alterations underpin apathy and depression in de novo parkinsonian patients is unknown. The objectives of this study were to investigate whether apathy and depression in de novo parkinsonian patients are related to structural alterations and how structural abnormalities relate to serotonergic or dopaminergic dysfunction.

METHODS

We compared the morphological and microstructural architecture in gray matter using voxel-based morphometry and diffusion tensor imaging coupled with white matter tract-based spatial statistics in a multimodal imaging case-control study enrolling 14 apathetic and 13 nonapathetic patients with de novo Parkinson's disease and 15 age-matched healthy controls, paired with PET imaging of the presynaptic dopaminergic and serotonergic systems.

RESULTS

De novo parkinsonian patients with apathy had bilateral microstructural alterations in the medial corticostriatal limbic system, exhibiting decreased fractional anisotropy and increased mean diffusivity in the anterior striatum and pregenual anterior cingulate cortex in conjunction with serotonergic dysfunction. Furthermore, microstructural alterations extended to the medial frontal cortex, the subgenual anterior cingulate cortex and subcallosal gyrus, the medial thalamus, and the caudal midbrain, suggesting disruption of long-range nondopaminergic projections originating in the brainstem, in addition to microstructural alterations in callosal interhemispheric connections and frontostriatal association tracts early in the disease course. In addition, microstructural abnormalities related to depressive symptoms in apathetic and nonapathetic patients revealed a distinct, mainly right-sided limbic subnetwork involving limbic and frontal association tracts.

CONCLUSIONS

Early limbic microstructural alterations specifically related to apathy and depression emphasize the role of early disruption of ascending nondopaminergic projections and related corticocortical and corticosubcortical networks which underpin the variable expression of nonmotor and neuropsychiatric symptoms in Parkinson's disease. © 2019 International Parkinson and Movement Disorder Society.

Age and time course of long-term motor and nonmotor complications in Parkinson disease

Objective

To determine the time course of hazard for motor and nonmotor milestones of Parkinson disease (PD) in the long term and to investigate whether risk scales nonlinearly with time is instrumental in identifying changes in pathological processes and evaluating disease-modifying therapies in PD.

Methods

Outpatients with PD at the Lyon University Movement Disorders Center were evaluated for 7 clinical milestones in this retrospective cohort study, encompassing 4 domains of PD progression: (1) motor (motor fluctuations, dyskinesias); (2) axial (postural instability and falls, freezing of gait); (3) neuropsychiatric (impulse control disorders, hallucinations); and (4) cognitive (dementia) complications. For each complication, we estimated the outcome-specific hazard using parsimonious smooth parametric Poisson regression models allowing for nonlinear scaling over disease duration, age at diagnosis, current age, and their interaction.

Results

A total of 1,232 patients with PD experienced 1,527 disease-related complications in up to 12 years of follow-up. Specific to each complication, hazard rates increased dramatically starting from diagnosis and were highest for motor fluctuations and lowest for dementia up to 6 years after diagnosis in patients aged 65 years at diagnosis. Nonlinear patterns indicated dramatic changes in the course of PD after 5 years and predicted more severe axial prognosis after 70 years and for motor fluctuations, dyskinesias, and impulse control disorders before 60 years at diagnosis.

Conclusion

Time course of motor and nonmotor milestones in PD is determined by disease duration and age at diagnosis in nonlinear patterns and their interaction. This indicates disease- and age-specific thresholds across the multiple neurodegenerative processes accumulating in PD at different paces.

What a neurologist should know about PET and SPECT functional imaging for parkinsonism: A practical perspective

The diagnosis of a parkinsonian syndrome based on clinical criteria remains sometimes difficult, especially at disease onset. Brain or heart molecular imaging techniques (SPECT or PET) can provide a major help to improve and speed up diagnosis, influencing treatment strategies. Presynaptic dopaminergic imaging using either [¹⁸F]-Dopa PET or ¹²³I -2β-Carbomethoxy-3β-(4-Iodophenyl)- N-(3-Fluoropropyl) Nortropane ([¹²³I]-Ioflupane)SPECT demonstrates or rules out the presence of a dopaminergic degenerative process. This allows to distinguish Parkinson's disease, Parkinson "plus" syndromes and dementia with Lewy bodies (reduced radiotracers binding) from essential tremor, psychogenic, post-neuroleptic or vascular parkinsonisms, dopa-responsive dystonia and Alzheimer's disease (normal radiotracers binding). For differential diagnosis between Parkinson's disease and Parkinson "plus" syndromes, brain molecular imaging with [¹⁸F]-Fluorodeoxyglucose ([¹⁸F]-FDG) PET or ^99mTc-HMPAO SPECT can provide useful information, whereas [¹⁸F]-Dopa PET or [¹²³I]-Ioflupane does not separate these entities. Finally, sympathetic cardiac [¹²³I]-Metaiodobenzylguanidine ([¹²³I]-MIBG) scintigraphy or SPECT can help distinguishing Parkinson's disease and dementia with Lew bodies (decreased binding) from multiple system atrophy and progressive supranuclear palsy (normal binding). New radiotracers notably those targeting the pathological process itself such as Tau aggregates are under development and may provide interesting informations to delineate the different Parkinson "plus" syndromes.

Origin and genetic structure of a recovering bobcat (Lynx rufus) population

Genetic analyses can provide important insights into the demographic processes that underlie recovering populations of mammals of conservation concern such as felid species. To better understand the recent and rapid recovery of bobcats (Lynx rufus (Schreber, 1777)) in Ohio, we analyzed samples from four states in the lower Great Lakes Region using 12 microsatellite DNA loci and a portion of the mtDNA control region. Our results showed that a newly established population of bobcats in the eastern part of Ohio was genetically distinct from a multistate population distributed across Kentucky, southern Ohio, West Virginia, and western Pennsylvania. There was no direct genetic evidence of a bottleneck or inbreeding in this population. A lack of private alleles and only slightly lower levels of allelic richness and heterozygosity compared with its neighbors suggest that the eastern Ohio population likely originated from the migration of relatively large numbers of individuals from a source population rather than re-emerging from an undetected residual population. We recommend that a management plan should define the areas occupied by the two populations in Ohio as separate management units at least for the near future.

[Ultrasound topometric measurements of thoracic kyphosis and lumbar lordosis in school children with normal and insufficient posture]

AIM

The posture of school children was examined in order to establish whether possible differences in clinically normal and insufficient posture can be detected by means of ultrasound topometry.

METHOD

105 healthy school children (56 female, 49 male) with an average age of 8 years (+/- 0.9) were examined. To classify the children as having sufficient or insufficient posture the Matthiass posture test was used. While the child stood in a relaxed position, the profile of the spine was measured with a topometric digitiser, recording each spinal processus from C7 to L5.

RESULTS

42 children (22 female, 20 male) showed an insufficient posture during the Matthiass test. The topometrically measured angles of kyphosis and lordosis were significantly smaller in these children, corresponding to a clinically greater thoracic kyphosis and lumbar lordosis. No significant differences in the lateral and anterior-posterior trunk deviation, nor in the range of trunk sway in the relaxed standing position could be observed.

CONCLUSION

Using ultrasound topometry, the posture of children with sufficient and insufficient posture can be differentiated by measuring, the angles of kyphosis and lordosis. This quantification could be used for objective monitoring of the posture.

TRANSPLANTED MHC CLASS I-DEFICIENT NONOBESE DIABETIC MOUSE ISLETS ARE PROTECTED FROM AUTOIMMUNE INJURY IN DIABETIC NONOBESE RECIPIENTS1

The injury of transplanted islets may occur by both autoimmune and alloimmune processes directed against MHC targets. To examine the role of MHC class I in islet graft injury, we transplanted syngeneic and allogeneic beta2-microglobulin-deficient islets into diabetic nonobese diabetic (NOD) mice. Loss of graft function was observed within 14 days using allogeneic C57BL/6 and BALB/c MHC class I deficient as well as wild-type MHC class I-bearing NOD donor islets. However, islets isolated from MHC class I-deficient NOD mice (NOD-B2 m-/-) survived indefinitely when transplanted under the kidney capsule of diabetic NOD recipients. Transplanted NOD-B2 m-/- islets were surrounded by a nondestructive periinsular infiltrate that expressed interleukin-4 in addition to interferon-gamma. These studies demonstrate the primary role of MHC class I molecules in causing autoimmune destruction or recurrent diabetes in transplanted islets.

[Measurement of spinal anteflexion in school children by ultrasound topometry]

AIM

The anteflexion of the spine in normal schoolchildren was examined by 3D real-time ultrasound topometry to see if differences in the form of restrictions of anteflexion could be detected.

METHODS

102 schoolchildren at the age of 7 to 9 years volunteered to the study. We measured the spinal anteflexion by recording the row of the spines (C7-L5) in a maximally flexed position with a topometric digitiser. By computer-aided data analysis the curvature of the spinal line was reproduced by lined up radii.

RESULTS

In the sagittal plane the spinal line in anteflexed position showed a single curvature in 8 cases. In 94 cases the spinal line was subdivided into three curvatures (X1, X2, X3) with less mobility of the region from the middle to the lower thoracic segments. For these less mobile segments we calculated a mean relative anteflexion (X2/[(X1 + X3)/2]) of 0.36 (+/- 0.18). In seven children (6.8%) with clinically indirect signs of scoliosis the anteflexion was reduced and in 4 cases out of the standard deviation. For the relative anteflexion the Pearson's correlation coefficient of the measurement 1 and the direct control-measurement was 0.86 (p < 0.001).

CONCLUSION

By ultrasound topometric measurement of the spinal anteflexion in schoolchildren we are able to identify cases with less ability of anteflexion. Because a restriction of anteflexion is discussed in the pathogenesis of idiopathic scoliosis, a follow up of these children seems to be usefully.

Ultrasonic sensor properties characterized by a PC-controlled scanning measuring system

The use of ultrasonic sensors for process control is currently widespread for flow, level or distance measurements. Recently, interest has increased, too in the application of ultrasonic sensors to concentration measurements in complex liquids. In this application there are high demands for a defined and stable quality of the properties of both the sensor transfer function and the sound field characteristic. For a detailed investigation and characterization of ultrasonic sensor propertiess, an efficient PC-controlled measuring system was developed by the Institut fur Automation und Kommunikation (IFAK). In this contribution, this high performance approach is presented to make visible the vibrating ultrasonic sensor surface as well as the sound field in front of acoustic sensors in liquids.

In-line concentration measurement in complex liquids using ultrasonic sensors

Recently there has been increased demand for chemical sensors measuring in-line the concentration of selected substances in complex liquids in order to guarantee a high product quality in the process industry. At present there is a great interest in acoustic sensor systems for concentration measurements. This article presents a new ultrasonic sensor system consisting of a miniaturized multi-sensor arrangement for the comprehensive acoustic characterization of liquid mixtures. The sensor system measures sound velocity, impedance coefficient, attenuation coefficient and temperature.

Evaluation of chronic tears of the rotator cuff by ultrasound

The diagnosis of chronic lesions of the rotator cuff is challenging. We have developed a new index to improve the sonographic diagnosis of chronic tears of the cuff.

In a pilot study, we examined 50 asymptomatic healthy volunteers by ultrasound to establish the diameter of the rotator cuff in relation to the tendon of the long head of biceps. Subsequently, the index was calculated in 64 patients who had had shoulder pain for more than three months caused by clinically diagnosed lesions of the rotator cuff. The compensatory hypertrophy of the biceps tendon was quantified sonographically in relation to the diameter of the cuff.

Comparison with the contralateral shoulder revealed a significantly higher biceps rotator-cuff ratio (p < 0.05) for patients with torn rotator cuffs. A ratio greater than 0.8 was considered pathological (index positive); the mean ratio in the control group was 0.43. The sensitivity of a positive index was 97.8%, the specificity 63.2%, the positive predictive value 86.3%, and the negative predictive value 92.4% in comparison with surgical findings.

Use of the index improves sensitivity in the diagnosis of chronic tears of the cuff by ultrasound.

Evaluation of chronic tears of the rotator cuff by ultrasound. A new index

The diagnosis of chronic lesions of the rotator cuff is challenging. We have developed a new index to improve the sonographic diagnosis of chronic tears of the cuff. In a pilot study, we examined 50 asymptomatic healthy volunteers by ultrasound to establish the diameter of the rotator cuff in relation to the tendon of the long head of biceps. Subsequently, the index was calculated in 64 patients who had had shoulder pain for more than three months caused by clinically diagnosed lesions of the rotator cuff. The compensatory hypertrophy of the biceps tendon was quantified sonographically in relation to the diameter of the cuff. Comparison with the contralateral shoulder revealed a significantly higher biceps rotator-cuff ratio (p < 0.05) for patients with torn rotator cuffs. A ratio greater than 0.8 was considered pathological (index positive); the mean ratio in the control group was 0.43. The sensitivity of a positive index was 97.8%, the specificity 63.2%, the positive predictive value 86.3%, and the negative predictive value 92.4% in comparison with surgical findings. Use of the index improves sensitivity in the diagnosis of chronic tears of the cuff by ultrasound.

Protective and destructive effects of microbial infection in insulin-dependent diabetes mellitus

Insulin-dependent diabetes mellitus (IDDM) is a T-cell mediated autoimmune disease, which results in the destruction of the islet beta-cells. The major histocompatibility complex (MHC) encodes the major susceptibility gene in IDDM. The concordance rate for diabetes in identical twins is 30-50% and in inbred animal models of disease the incidence rate is 20-80%. These results emphasize a role for environmental factors in the disease process. It has long been suggested that IDDM in humans may be caused by-viral infections. While considerable progress has been made in defining the genetics of IDDM, our understanding of the role of environmental factors, which might provide a more direct approach to therapy is considerably lacking. We suggest that (1) the density and affinity of epitopes derived from microbial antigens that bind to MHC molecules; (2) their cross-reactivity with beta-cell antigens; and (3) the nature of immunoregulatory cytokines induced by the microbial infections are the primary factors in the induction of either effector or protective T cells in IDDM.

Modulation and detection of IDDM by membrane associated antigens from the islet beta cell line NIT-1

We have utilized the NOD islet beta-cell line NIT-1 to monitor beta-cell specific autoantibodies and to investigate the modulation of IDDM in NOD mice by NIT-1 membrane associated antigens. The sera from diabetic but not from pre-diabetic or protected NOD mice strongly stained NIT-1 cells in FACS analysis. The cell surface antigens on NIT-1 cells were trypsin-sensitive. NIT-1 cells could not be stained by anti-mouse GAD67 antibody; however, we could demonstrate the presence of GAD65 and GAD67 mRNA by RT-PCR. Longitudinal analysis of anti-NIT-1 antibodies showed that these antibodies were present in the neonates but disappeared after weaning. Sonicated NIT-1 cell membrane preparations protected NOD mice from diabetes when injected intravenously in 5 week old mice. The protection was associated with reduced cytotoxic activity and elevated Th2-like responses as indicated by IgG1 antibodies against the NIT-1 cells. Subcutaneous injection of sonicated NIT-1 membranes or the injection of control red blood cell membranes failed to induce protection. We conclude that NIT-1 cell membranes do not express GAD but contain other antigens that are important in the development and prevention of IDDM. These antigens could be useful for the diagnosis of diabetes by monitoring autoantibody levels and for the modulation of IDDM by immunotherapy.