Comparative Olfactory Profiles in Parkinson's Disease and Drug-Induced Parkinsonism

OBJECTIVE

Drug-induced parkinsonism (DIP) is a frequently encountered diagnostic possibility when considering Parkinson's disease (PD). While olfactory dysfunction is a common clinical feature in PD, the comparison of olfactory function between the two conditions remains insufficient. This study aimed to compare olfactory function, including threshold, discrimination, and identification (TDI) profiles, between PD and DIP.

METHODS

Consecutive patients with drug-naïve PD (n = 78) or DIP (n = 31) confirmed through dopamine transporter imaging were enrolled in this study. The YSK olfactory function (YOF) test, composed of TDI domains culturally familiar odorants to Koreans, was administered to all patients.

RESULTS

In the study population, patients with DIP were significantly older than patients with PD. Over 70% of patients in each group had hyposmia or anosmia, and there was no significant difference in the occurrence of olfactory dysfunction between the two groups. In addition, there were no differences in the total YOF score and threshold score between the two groups. Meanwhile, the PD group had a significantly lower discrimination and identification score than the DIP group after adjusting for age, sex, the existence of diabetes, disease duration, and cognitive function.

CONCLUSION

This study demonstrated that detailed olfactory profiles are different in PD and DIP, even though olfactory dysfunction can be observed in both conditions.

Evidence of Inflammation in Parkinson’s Disease and Its Contribution to Synucleinopathy

Accumulation of alpha-synuclein (αSyn) protein in neurons is a renowned pathological hallmark of Parkinson’s disease (PD). In addition, accumulating evidence indicates that activated inflammatory responses are involved in the pathogenesis of PD. Thus, achieving a better understanding of the interaction between inflammation and synucleinopathy in relation to the PD process will facilitate the development of promising disease-modifying therapies. In this review, the evidence of inflammation in PD is discussed, and human, animal, and laboratory studies relevant to the relationship between inflammation and αSyn are explored as well as new therapeutic targets associated with this relationship.

Role of NLRP3 Inflammasome in Parkinson's Disease and Therapeutic Considerations

Parkinson's disease (PD) is the second most common neurodegenerative disease, with two main pathological features: misfolded α-synuclein protein accumulation and neurodegeneration. Inflammation has recently been identified as a contributor to a cascade of events that may aggravate PD pathology. Inflammasomes, a group of intracellular protein complexes, play an important role in innate immune responses to various diseases, including infection. In PD research, accumulating evidence suggests that α-synuclein aggregations may activate inflammasomes, particularly the nucleotide-binding oligomerization domain-leucine-rich repeat-pyrin domain-containing 3 (NLRP3) type, which exacerbates inflammation in the central nervous system by secreting proinflammatory cytokines like interleukin (IL)-18 and IL-1β. Afterward, activated NLRP3 triggers local microglia and astrocytes to release additional IL-1β. In turn, the activated inflammatory process may contribute to additional α-synuclein aggregation and cell loss. This review summarizes current research evidence on how the NLRP3 inflammasome contributes to PD pathogenesis, as well as potential therapeutic strategies targeting the NLRP3 inflammasome in PD.

Intrathecal delivery of a mutant micro-opioid receptor activated by naloxone as a possible antinociceptive paradigm

Direct injection of double-stranded adeno-associated virus type 2 (dsAAV2) with a mu-opioid receptor (MOR) mutant [S4.45(196)A], and a reporter protein (enhanced green fluorescent protein) into the spinal cord (S2/S3) dorsal horn region of ICR mice resulted in antinociceptive responses to systemic injection of opioid antagonist naloxone without altering the acute agonist morphine responses and no measurable tolerance or dependence development during subchronic naloxone treatment. To develop further such mutant MORs into a therapeutic agent in pain management, a less invasive method for virus delivery is needed. Thus, in current studies, the dsAAV2 was locally injected into the subarachnoid space of the spinal cord by intrathecal administration. Instead of using the MORS196A mutant, we constructed the dsAAV2 vector with the MORS196ACSTA mutant, a receptor mutant in which naloxone has been shown to exhibit full agonistic properties in vitro. After 2 weeks of virus injection, naloxone (10 mg/kg s.c.) elicited antinociceptive effect (determined by tail-flick test) without tolerance (10 mg/kg s.c., b.i.d. for 6 days) and significant withdrawal symptoms. On the other hand, subchronic treatment with morphine (10 mg/kg s.c., b.i.d.) for 6 days induced significant tolerance (4.8-fold) and withdrawal symptoms. Furthermore, we found that morphine, but not naloxone, induced the rewarding effects (determined by conditioned place preference test). These data suggest that local expression of MORS196ACSTA in spinal cord and systemic administration of naloxone has the potential to be developed into a new strategy in the management of pain without addiction liability.

The comparison of motor performance between part and whole tasks in elderly persons

OBJECTIVE

When teaching clients a multistep functional task, therapists tend to break down the task into part tasks with discrete movements. The purpose of this study was to compare the kinematic performance between part and whole tasks in elderly persons.

METHOD

A counterbalanced repeated-measures design was used. Twenty elderly persons without motor problems (7 men, 13 women) performed a signature task in two conditions. For the part-task condition, the participants did the task in a step-by-step manner: (a) reach for a pen, (b) bring the pen to the paper, and (c) sign the name. For the whole-task condition, the participants performed the task in an integrated continuous flow. Kinematic performances for two movement segments (i.e., reaching for the pen, bringing the pen to the paper) were compared between conditions.

RESULTS

Generally, the whole-task condition elicited a more efficient, more forceful, and smoother movement than the part-task condition.

CONCLUSION

The results suggest the importance of keeping a multistep functional task whole.

Recombinant adeno-associated virus vector expressing glial cell line-derived neurotrophic factor reduces ischemia-induced damage

To explore the potential of using the recombinant adeno-associated viral (rAAV) vector, expressing glial cell line-derived neurotrophic factor (GDNF) as the gene therapy for stroke, we injected rAAV vectors expressing GDNF (rAAV-GDNF) into the cortex of rats which had been experiencing transient bilateral common carotid artery ligation and right middle cerebral artery ligation for 90 min. GDNF levels in cortical tissues of rAAV-GDNF-injected animals were significantly higher than in the control animals injected with rAAV-expressing lacZ (rAAV-lacZ), indicating that rAAV can deliver and express the GDNF gene in cortical tissues. Triphenyltetrazolium chloride tissue stain analysis revealed that the rAAV-delivered GDNF gene could rescue the brain tissues from ischemia-induced injury. Cortical tissues which received rAAV-GDNF injections had both significantly smaller total volumes of infarction and smaller areas of infarction on each brain slice than those which were injected with rAAV-lacZ. An in situ labeling analysis demonstrated significantly less apoptotic cells in cortical tissues rescued by rAAV-GDNF, indicating prevention of apoptosis as the mechanism of cortical cell protection. Moreover, immunohistochemistry staining of Neu-N indicated that the rescued brain tissues contained the same number of Neu-N-positive neuronal cells as contralateral undamaged brain tissues. This provides strong evidence that cortical neuronal cells can be rescued by GDNF gene therapy. Indeed, these findings show that the rAAV is a potential delivery vector of GDNF gene for the therapy of stroke.

The effect of context on skill acquisition and transfer

OBJECTIVE

A major concern of occupational therapy is the identification of context characteristics that optimize performance. The purpose of this study was to examine the effect of context on skill acquisition and transfer.

METHOD

Forty college students without disabilities (12 men, 28 women) were randomly assigned to the task of learning to use chopsticks in either a natural or a simulated context. Each participant practiced 60 trials in an acquisition phase on 1 day and was tested on a transfer task 24 hr after the acquisition phase. Their performances in the acquisition and transfer phases were measured with the variables of success rate and reaching kinematics.

RESULTS

The natural context elicited significantly larger improvement of success rate in the acquisition phase and a significantly higher success rate in the transfer phase than the simulated context. No major difference was found in kinematic variables between the two contexts.

CONCLUSION

These results suggested the use of natural contexts to facilitate the outcome of motor skill learning.

Kinetic study of alterations in the host RNA polymerase and protein synthesis during phage Xp 10 infection

We monitored the compositional change of host RNA polymerase in Xp 10 infected cells by one-step immunoprecipitation with core enzyme-specific antiserum. Results showed a rapid loss of sigma subunit from the RNA polymerase complex by 3 min after infection. In addition, some putative binding proteins were reduced to various extents. In contrast, increasing levels of several other polypeptides were detected. The de novo host protein synthesis was inhibited within 1 min after Xp 10 infection. On the other hand, a sequential expression of phage specific proteins was found and can be categorized as early, middle, and late stage. The alteration of host RNA polymerase and the shutdown of early class proteins took place in parallel.