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Circadian rhythms have been shown in the subthalamic nucleus (STN) in Parkinsons disease (PD), but only a few studies have focused on the globus pallidus internus (GPi). This retrospective study investigates GPi circadian rhythms in a large cohort of subjects with PD (130 recordings from 93 subjects) with GPi activity chronically recorded in their home environment. We found a significant change in GPi activity between daytime and nighttime in most subjects (82.4%), with a reduction in GPi activity at nighttime in 56.2% of recordings and an increase in activity in 26.2%. GPi activity in higher frequency bands ( > 20 Hz) was more likely to decrease at night and in patients taking extended-release levodopa medication. Our results suggest that circadian fluctuations in the GPi vary across individuals and that increased power at night might be due to the reemergence of pathological neural activity. These findings should be considered to ensure successful implementation of adaptive neurostimulation paradigms in the real-world.

Despite a strong body of evidence supporting benefits of exercise to reduce severity of motor symptoms of Parkinson's Disease (PD) over time, research on the immediate impact of exercise as an adjunctive therapy for nonpharmacologic management of motor symptoms and mobility performance in people with PD is limited. The purpose of this study was to examine immediate effects of a single bout of high-cadence cycling on motor symptoms of PD and performance-based outcomes. Twenty individuals with idiopathic PD participated in a pretest/posttest study investigating immediate impacts of a single high-cadence cycling session on performance-based outcomes across multiple domains of motor function, mobility, and balance. Outcomes were analyzed based on time since last dose of levodopa/carbidopa medication. Immediate improvements were observed in motor symptoms of PD with significant improvements in performance across multiple balance systems, dynamic gait, and upper-extremity coordination following a cycling intervention. [ABSTRACT FROM AUTHOR]

BACKGROUND: DATATOP was a study of early Parkinsons disease (PD) conducted in the 1980 s, before mandatory folic acid fortification in the United States. Our analysis of its baseline serum samples revealed a geometric mean vitamin B12 of 369 pg/mL and homocysteine (tHcy) of 9.5μmol/l. We also found that low B12 predicted greater worsening of ambulatory capacity (AC) and elevated tHcy (>15μmol/L) predicted greater declines in cognitive function. OBJECTIVE: We sought to measure B12 and tHcy in contemporary trial participants with early PD who had not started dopaminergic treatment and to determine whether these analytes were associated with clinical progression. METHODS: We measured B12 and tHcy from baseline and end-of-study blood samples from three recent clinical trials. RESULTS: Baseline geometric mean B12 levels for these studies ranged from 484- 618 pg/ml and for tHcy ranged from 7.4- 10μmol/L. Use of B12-containing supplements ranged from 41- 61%, and those taking supplements had higher B12 and lower tHcy. Those who began levodopa, but were not taking B12-supplements, had greater end-of-study tHcy. There was no association of baseline tHcy > 15μmol/L with annualized change in Montreal Cognitive Assessment and no association of baseline B12 tertiles with change in AC. CONCLUSIONS: In these longitudinal trials, B12 levels were higher than for DATATOP, due in large part to increased B12-supplement intake, while tHcy levels were similar. Initiation of levodopa was associated with increases of tHcy in those not taking a B12-containing supplement. These smaller studies did not replicate prior findings of low B12 and elevated tHcy with features of progression, possibly due to higher baseline B12.

BackgroundTremor in Parkinson's disease (PD) is commonly seen in the upper extremities and can involve the lower extremities and mouth. We present a case of a patient with idiopathic PD who presented with abdominal tremor.Case reportA 40-year-old man with a 2-year history of subjective weakness and stiffness in the right arm and leg, followed by emergence of a right hand tremor, subsequently developed abdominal tremor. Patient experienced marked improvement of both abdominal and hand tremor and mobility of the right limbs with levodopa.DiscussionOur case report serves as the second only published report of abdominal tremor in an idiopathic PD patient.HighlightsTremor in Parkinson's disease (PD) commonly affects the upper and lower extremities and mouth. We describe a 40-year-old man with PD who developed abdominal tremor which was brought under control with levodopa. This case is one of only two published reports of abdominal tremor in PD.

A sustainable HPTLC-densitometric method was developed for quantitative determination of Quetiapine (QUET), Levodopa (LD) and Carbidopa (CD) in presence of Dopamine (DOP) as an internal standard. This applicable technique was achieved by spiking human plasma and extraction was performed using the protein precipitation approach. The mobile phase used was acetone, dichloromethane, n-butanol, glacial acetic acid and water (3: 2.5: 2: 2: 1.75, by volume). Method validation was done according to US-FDA guidelines and was able to quantify Quetiapine, Levodopa and Carbidopa in the ranges of 100–4000, 200–8000 and 30–1300 ng/mL, respectively. Bioanalytical method validation parameters were assessed for the studied drugs. Finally, the analytical suggested methodology was evaluated using various green and white analytical chemistry metrics and other tools, such as the green solvent selection tool, analytical eco-scale, green analytical procedure index, analytical greenness metric approach and the red–green–blue algorithm tool. The results revealed that the applied analytical method had a minor impact on the environment and is a relatively greener option than other previously reported chromatographic methods. [ABSTRACT FROM AUTHOR]

Background: The search for neuroprotective treatments for Parkinson's disease (PD) still relies largely on motor disability scales. A limitation of these tools is the strong influence of symptomatic dopaminergic treatment effects. Drawing on a wealth of published information, we conducted a systematic review and metaanalysis of motor progression in PD and its relationships with dopaminergic therapy. Methods: We searched Medline, Embase, and Central to identify 84 publications with adequate serial motor scores to calculate progression, expressed as an increase in the percentage of maximum disability. Results: A random-effects model showed motor progression at 2.0% p.a. (95% CI 1.7-2.4%). There were no significant differences by baseline age, sample size, or observation period. However, untreated patients, in 8 publications, progressed at 4.5% p.a. compared to 1.6% p.a. in 76 studies containing individuals on dopaminergic drugs (p = 0.0004, q = 0.003). This was supported by research on phenoconversion in prodromal PD, where motor progression exceeded 5% p.a. in the 2 years before diagnosis. Starting levodopa improved pre-treatment disability by 40.3 ± 15.2%. Practically defined off state measurements increase faster than on scores by a modest degree (p = 0.05). Conclusion: This survey suggests that accurate long-term measurements of motor progression to assess disease-modifying therapies can be conducted despite the sequential commencement of dopaminergic drugs and sample attrition over time. While study designs involving prodromal or untreated PD avoid confounding effects of symptomatic treatment, different assumptions about motor progression may be needed. A defined off state with the levodopa test dose method maximizes information about the medication cycle once dopaminergic therapy has begun. [ABSTRACT FROM AUTHOR]

Advanced Parkinson´s disease (PD) is often complicated by fluctuations of disability depending on plasma levels of levodopa. For most patients OFF phases with worsening of tremor and immobility, but also pain, depression, autonomic symptoms are troublesome. While adjustments of levodopa administrations can relief such fluctuations for some time, "on demand" therapies become more and more important. These "on demand" therapies should provide fast and efficacious relief. During the past years, new options for on demand therapies in PD-associated OFF episodes have been developed, including new formulations of levodopa and apomorphine to provide fast and readily accessible on demand treatment. In this narrative review, the challenges of the treatment of PD-associated fluctuations and OFF states are addressed, with a special focus on sublingual apomorphine (SL-APO) including the results from recent clinical trials. [ABSTRACT FROM AUTHOR]

Background: There has been a long debate whether delaying treatment with levodopa prevents motor complications in Parkinson's disease (PD). Objectives: We performed a meta‐analysis on randomized clinical trials (RCTs) that compared early‐ versus delayed‐start treatment with levodopa in PD. Methods: A systematic review was conducted in PubMed, EMBASE, and Web of Science databases from inception to July 1, 2023. Only RCTs that compared early and delayed levodopa treatment in PD were included. Non‐randomized comparisons from follow‐up studies were included as well. Our primary outcomes were occurrence of overall motor complications, motor fluctuations, and dyskinesias. Results: Seven studies with a total of 1149 patients (636 in the early‐start group and 513 in the delayed‐start) were included in our analysis. There was no difference between groups regarding motor complications (OR 1.39; 95% CI: 0.68–1.72; P = 0.37) or dyskinesias (OR 1.52; 95% CI: 0.90–2.57; P = 0.11). Motor fluctuations occurred less frequently in the early‐start group (OR 0.70; 95% CI: 0.52–0.95; P = 0.02). Nonetheless, on subgroup analysis of dopamine agonists, rate of dyskinesias was smaller in the delayed‐start group (OR 1.82; 95% CI: 1.08–3.07; P = 0.03). Conclusions: Delaying treatment with levodopa does not seem to prevent levodopa‐related motor complications in PD. Adjunct treatment with dopamine agonists may reduce the need for higher doses of levodopa and thus reduce the risk for dyskinesias but this practice is often associated with a higher frequency of adverse effects related to dopamine agonists. [ABSTRACT FROM AUTHOR]

Background: The ideal timing for initiating levodopa in newly diagnosed people with Parkinson's disease (PD) is uncertain due to limited data on the long‐term effects of levodopa. Objective: The aim was to investigate whether early levodopa initiation postpones mortality (primary outcome), the requirement of device‐aided therapies, and the incidence of PD‐related complications, such as fall‐induced injuries. Methods: Using nationwide claims data from Dutch hospitals (2012–2020), we grouped newly diagnosed PD individuals as "early initiators" (initiating levodopa within 2 years of diagnosis) or "nonearly initiators." We used the national death registry to assess mortality and health‐care claims to assess PD‐related complications and device‐aided therapies. We used marginal structural models to compare mortality and device‐aided therapy rates between groups, and a Poisson regression model to compare PD‐related complication rates. Results: Among 29,943 newly diagnosed PD individuals (mean age at diagnosis: 71.6, 38.5% female), there were 24,847 early and 5096 nonearly levodopa initiators. Over a median 4.25 years, 8109 (27.1%) died. The causal risk ratio for mortality was 1.04 (95% confidence interval [CI] 0.92–1.19) for early versus nonearly initiators. The risk ratio of receiving any device‐aided therapy was 3.19 (95% CI 2.56–5.80). No association was observed with incidence of PD‐related complications (incidence rate ratio: 1.00, 95% CI 0.96–1.05). Conclusions: Early levodopa initiation in PD does neither postpone nor accelerate mortality or PD‐related complications, nor does it precipitate earlier occurrence of PD‐related complications or mortality. However, we cannot exclude that the results were influenced by residual confounding due to unmeasured risk factors of mortality. [ABSTRACT FROM AUTHOR]

Rapid control of the content of Parkinson's drugs in biological fluids and pharmaceutical formulations is of great importance because changes in the concentration of these drugs affect their bioavailability and biopharmaceutical properties. Therefore, we presented a simple and convenient method for the ratiometric detection of carbidopa and levodopa for carbon dots (CDs) dual‐fluorescent emission. Dual‐emission CDs were prepared from chitosan using a microwave method, following which the surface was chemically modified with terephthalaldehyde. CDs had two strong well‐separated peaks at 445 and 510 nm. The relative measurement of carbidopa and levodopa was based on the static extinction of CDs at 445 nm and increase at 510 nm, respectively. The linear range for carbidopa measurement was 2.5–300 nM, with a limit of detection (LOD) of 2.1 nM, and a relative standard deviation (RSD) of 1.68%. Further, the linear range for levodopa measurement was equal to 3.0–400 nM, with LOD and RSD% of 2.8 nM and 3.5%, respectively. Also, selectivity of ratiometric sensor in the presence of interferences was investigated, which showed that the recovery of carbidopa and levodopa in serum and urine samples has changed between 96.80% and 116.24% with RSD% 0.11–0.77. CDs also provided good results for the determination of carbidopa and levodopa in real samples, and had high selectivity in the presence of possible interferences. [ABSTRACT FROM AUTHOR]

Background: The wearing-off phenomenon is a key driver of medication change for patients with Parkinson's disease (PD) treated with levodopa. Common first-line options include increasing the levodopa dose or adding a catechol-O-methyltransferase (COMT) inhibitor, but there are no trials comparing the efficacy of these approaches. We evaluated the effectiveness of adjunct opicapone versus an additional 100 mg levodopa dose in PD patients with early wearing-off using pooled data from 2 randomized studies. Methods: The ADOPTION study program included two similarly designed 4-week, open-label studies conducted in South Korea (NCT04821687) and Europe (NCT04990284). Patients with PD, treated with 3–4 daily doses of levodopa therapy and with signs of early wearing-off were randomized (1:1) to adjunct opicapone 50 mg or an additional dose of levodopa 100 mg. Patient-level data from the two studies were pooled. Results: The adjusted mean [SE] change from baseline to week 4 in absolute OFF time (key endpoint) was − 62.8 min [8.8] in the opicapone group and − 33.8 min [9.0] in the levodopa 100 mg group, the difference significantly favoring opicapone (− 29.0 [− 53.8, − 4.2] min, p = 0.02). Significant differences in the Movement Disorder Society—Unified Parkinson's Disease Rating Scale Part III subscore (− 4.1 with opicapone vs − 2.5 with levodopa 100 mg), also favored opicapone (− 1.7 [− 3.3, − 0.04], p < 0.05). Dyskinesia was the most frequently reported adverse event (opicapone 7.2% vs. levodopa 100 mg 4.2%). Conclusions: In these short-term trials, introducing adjunct opicapone was more effective at reducing OFF time than adding another 100 mg levodopa dose in PD patients with early signs of wearing-off. [ABSTRACT FROM AUTHOR]

Introduction: Parkinson's disease (PD) is a highly prevalent disease characterized by motor and non-motor symptoms; the latter include constipation, which is considered a prodromal symptom. On the other hand, sarcopenia, polypharmacy, and malnutrition due to deficits are common in PD and lead to poorer health and quality of life. Objective: to associate constipation and use of levodopa with nutritional status, sarcopenia, duration and stage of the disease, and polypharmacy in individuals with PD. Materials and methods: analytical cross-sectional observational study where an online survey was applied to 161 people suffering from PD. Results: a significant association is observed between constipation and BMI (p = 0.022), as well as between the use of levodopa with BMI (p = 0.049) and polypharmacy (p = 0.046). On the other hand, there is a relationship between the average time of PD diagnosis and constipation (p = 0.0047). Finally, there is a relationship between SARC-F score applied to those over 60 years of age (p = 0.0446) and the use of levodopa. Having sarcopenia, being overweight, and having had the disease for less than five years is associated with a higher probability of experiencing constipation, according to the logistic regression analysis (p > 0.005). Conclusion: nutritional assessment and subsequent follow-up is of vital importance to avoid complications that could be associated with levodopa use, constipation, and sarcopenia. [ABSTRACT FROM AUTHOR]

Methods: We conducted a double-blind, randomised, placebo-controlled crossover trial with healthy older adults (65-79 years, n = 35). Participants first learned a word list and were then administered long-acting L-DOPA (or placebo) before a full night of sleep. Before sleeping, a proportion of the words were re-exposed using a recognition test to strengthen memory. L-DOPA was active during sleep and the practice-recognition test, but not during initial learning. Results: The single dose of L-DOPA increased total slow-wave sleep duration by approximately 11% compared to placebo, while also increasing spindle amplitudes around slow oscillation peaks and around 1-4 Hz NREM spectral power. However, behaviourally, L-DOPA worsened memory of words presented only once compared to re-exposed words. The coupling of spindles to slow oscillation peaks correlated with these differential effects on weaker and stronger memories. To gauge whether L-DOPA affects encoding or retrieval of information in addition to consolidation, we conducted a second experiment targeting L-DOPA only to initial encoding or retrieval and found no behavioural effects. Discussion: Our results demonstrate that L-DOPA augments slow wave sleep in elderly, perhaps tuning coordinated network activity and impacting the selection of information for long-term storage. The pharmaceutical modification of slowwave sleep and long-term memory may have clinical implications. [ABSTRACT FROM AUTHOR]

Background: Among the different types of pain related to Parkinson's disease (PD), parkinsonian central pain (PCP) is the most disabling. Objectives: We investigated the analgesic efficacy of two therapeutic strategies (opioid with oxycodone‐ prolonged‐release (PR) and higher dose of levodopa/benserazide) compared with placebo in patients with PCP. Methods: OXYDOPA was a randomized, double‐blind, double‐dummy, placebo‐controlled, multicenter parallel‐group trial run at 15 centers within the French NS‐Park network. PD patients with PCP (≥30 on the Visual Analogue Scale [VAS]) were randomly assigned to receive oxycodone‐PR (up to 40 mg/day), levodopa/benserazide (up to 200 mg/day) or matching placebo three times a day (tid) for 8 weeks at a stable dose, in add‐on to their current dopaminergic therapy. The primary endpoint was the change in average pain intensity over the previous week rated on VAS from baseline to week‐10 based on modified intention‐to‐treat analyses. Results: Between May 2016 and August 2020, 66 patients were randomized to oxycodone‐PR (n = 23), levodopa/benserazide (n = 20) or placebo (n = 23). The mean change in pain intensity was −17 ± 18.5 on oxycodone‐PR, −8.3 ± 11.1 on levodopa/benserazide, and −14.3 ± 18.9 in the placebo groups. The absolute difference versus placebo was −1.54 (97.5% confidence interval [CI], −17.0 to 13.90; P = 0.8) on oxycodone‐PR and +7.79 (97.5% CI, −4.99 to 20.58; P = 0.2) on levodopa/benserazide. Similar proportions of patients in each group experienced all‐cause adverse events. Those leading to study discontinuation were most frequently observed with oxycodone‐PR (39%) than levodopa/benserazide (5%) or placebo (15%). Conclusions: The present trial failed to demonstrate the superiority of oxycodone‐PR or a higher dose of levodopa in patients with PCP, while oxycodone‐PR was poorly tolerated. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Background: It has been suggested that carbidopa at high blood concentrations may counter the therapeutic effect of levodopa in Parkinson's disease by entering the brain and blocking central levodopa conversion to dopamine. We previously demonstrated equivalent plasma levodopa concentration in patients with Parkinson's disease during 16 h of (1) intravenous carbidopa/levodopa (DIZ101) infusion, (2) subcutaneous carbidopa/levodopa (DIZ102) infusion or (3) intestinal carbidopa/levodopa gel infusion. Plasma levels of carbidopa were however approximately four times higher with DIZ101 and DIZ102 than with LCIG, and higher than those usually observed with oral levodopa/carbidopa. Objectives: To investigate if high carbidopa blood concentrations obtained with parenteral levodopa/carbidopa (ratio 8:1) counter the effect of levodopa on motor symptoms. Methods: Eighteen patients with advanced Parkinson's disease were administered DIZ101, DIZ102, and intestinal levodopa/carbidopa gel for 16 h on different days in randomized order. Video recordings of a subset of the motor examination in the Unified Parkinson's Disease Rating Scale (UPDRS) were evaluated by raters blinded for treatment and time. Motor function was also measured using a wrist‐worn device monitoring bradykinesia, dyskinesia, and tremor (Parkinson KinetiGraph). Results: There was no tendency for poorer levodopa effect with DIZ101 or DIZ102 as compared to LCIG. Conclusion: Although DIZ101 or DIZ102 causes approximately four times higher plasma carbidopa levels than LCIG, patients responded equally well to all treatments. The results do not indicate that high plasma carbidopa levels hamper the motor efficacy of levodopa. [ABSTRACT FROM AUTHOR]

Background: Dopaminergic responsiveness is a defining feature of Parkinson's disease (PD). However, there is limited information on how this evolves over time. Objectives: To examine serial dopaminergic responses, if there are distinct patterns, and which factors predict these. Methods: We analyzed data from the Parkinson's Progression Markers Initiative on repeated dopaminergic challenge tests (≥24.5% defined as a definite response). Growth‐mixture modeling evaluated for different response patterns and multinomial logistic regression tested for predictors of these clusters. Results: 1525 dopaminergic challenge tests were performed in 336 patients. At enrolment, mean age was 61.2 years (SD 9.6), 66.4% were male and disease duration was 0.5 years (SD 0.5). 1 to 2 years after diagnosis, 48.0% of tests showed a definite response, but this proportion increased with longer disease duration (51.1–74.3%). We identified 3 response groups: "Striking" (n = 29, 8.7%); "Excellent" (n = 110; 32.7%) and "Modest" (n = 197, 58.6%). Significant differences were as follows: striking responders commenced treatment earlier (P = 0.02), were less likely to be on dopamine agonist monotherapy (P = 0.01), and had better cognition (P < 0.01) and activities of daily living (P = 0.01). Excellent responders had higher challenge doses (P = 0.03) and were more likely to be on combination therapy (P < 0.01). Conclusion: Three distinct patterns of the dopaminergic response were observed. As the proportion of PD cases with definite dopa responsiveness increased over time, the initial treatment response may be an unreliable diagnostic aid. [ABSTRACT FROM AUTHOR]

Innovative therapeutic strategies are urgently needed for Parkinson's disease due to limited efficacy of current treatments and a weak therapeutic pipeline. In this forum article, we propose targeting tyrosine hydroxylase phosphorylation as a novel mechanism of action to address this critical need. [ABSTRACT FROM AUTHOR]

Objective: The main endpoint of the study was to evaluate if a daily intake of whey protein-based dietary supplement causes a worse response to levodopa in people with Parkinson's Disease (PWPD) Background: In PWPD, the competition between large neutral aminoacids and levodopa at intestinal absorption level may interfere with dopaminergic therapy's (DRT) effect; therefore, protein redistribution dietary regimen has been suggested. Many dietary supplementations are available to help people in balancing the protein intake and overcoming muscle mass loss. However, most of the products contain protein and could potentially affect levodopa action in PWPD. Methods: We performed a randomised single blind monocentric study on PWPD admitted in the rehabilitative unit for a 4-week multidisciplined intensive aerobic rehabilitation treatment. All patients received a standard protein redistribution dietary regimen plus a whey protein-based oral formula (N = 26) or Magnesium (N = 25) twice daily for 28 days. Neurological assessment and physical evaluation were conducted before (T0) and after (T1) rehabilitative treatment; DRT was recorded T0 and T1 as well. The delta of changes within groups in neurological (UPDRS III) and physical (TUG, 6 MW) evaluation scales was compared between groups. Results: Groups were comparable at baseline in clinical and demographic data; at T1, both groups showed a decrease in UPDRS III, TUG and 6 MWT and no differences between deltas were found. DRT remained stable in both groups. Conclusions: Our results show that whey protein supplementation does not interfere with DRT's efficacy and can be used in PWPD who need a protein supplementation without restrictions in intake hours. [ABSTRACT FROM AUTHOR]

Many studies show either the absence, or very low levels of, SARS-CoV-2 viral RNA and/or antigen in the brain of COVID-19 patients. Reports consistently indicate an abortive infection phenomenon in nervous cells despite the fact that they contain the SARS-CoV-2 receptor, ACE2. Dopamine levels in different brain regions are in the range of micromolar to millimolar concentrations. We have shown that sub-micromolar to low micromolar concentrations of dopamine or its precursor (levodopa) time- and dose-dependently inhibit the activity of SARS-CoV-2 main protease (Mpro), which is vital for the viral life cycle, by forming a quinoprotein. Thiol detection coupled with the assessment of Mpro activity suggests that among the 12 cysteinyl thiols, the active site, Cys145-SH, is preferentially conjugated to the quinone derived from the oxidation of dopamine or levodopa. LC-MS/MS analyses show that the Cys145-SH is covalently conjugated by dopamine- or levodopa- o -quinone. These findings help explain why SARS-CoV-2 causes inefficient replication in many nerve cell lines. It is well recognized that inhaled pulmonary drug delivery is the most robust therapy pathway for lung diseases. CVT-301 (orally inhaled levodopa) was approved by the FDA as a drug for Parkinson's patients prior to the outbreak of COVID-19 in 2018. Based on the fact that SARS-CoV-2 causes inefficient replication in the CNS with abundant endogenous Mpro inhibitor in addition to the current finding that levodopa has an Mpro-inhibitory effect somewhat stronger than dopamine, we should urgently investigate the use of CVT-301 as a lung-targeting, COVID-19, Mpro inhibitor. [Display omitted] • The reason SARS-CoV-2 fails to cause productive infection in many nerve cell lines is unclear. • Neurons are rich in dopamine which inhibits Mpro by forming a quinoprotein. • Dopamine- o -quinone preferentially reacts with the active site, Cys145-SH, of 12 Mpro cysteinyl thiols. • The dopamine precursor, levodopa, exhibits an inhibitory effect stronger than that of dopamine itself. • Orally inhaled levodopa (the FDA-approved CVT-301) could be repurposed as an Mpro-inhibitor of COVID-19 that targets the lung. [ABSTRACT FROM AUTHOR]