Disease severity and prefrontal cortex activation during obstacle negotiation among patients with Parkinson's disease: Is it all as expected?

BACKGROUND

Previous reports indicate that patients with Parkinson's disease (PD) activate the prefrontal cortex (PFC) during complex activities such as obstacle negotiation to compensate for impaired motor function. However, the influence of disease severity on PFC activation has not been systematically evaluated. Here, we examined the effects of disease severity on PFC activation during obstacle negotiation.

METHODS

74 patients with PD (age 68.26 ± 7.54 yrs; 62.2% men) were divided into three groups based on Hoehn and Yahr stages. All patients walked along an obstacle course while negotiating anticipated and unanticipated obstacles (long/low available response time) at heights of 50 mm and 100 mm. PFC activation was measured using functional near-infrared spectroscopy (fNIRS) and was compared between groups and tasks using mixed model analyses.

RESULTS

Participants with more advanced PD (i.e., Hoehn & Yahr 3) had higher PFC activation levels when negotiating anticipated obstacles, compared to participants with milder PD (i.e., Hoehn & Yahr 1, 2) (p < 0.001). Moreover, higher LEDD correlated with higher prefrontal activation during the higher anticipated obstacle. In contrast, during the negotiation of unanticipated obstacles, the differences in PFC activation were not associated with disease severity in a linear manner.

CONCLUSIONS

The present study suggests that with increased disease severity, patients with PD rely more on the PFC when negotiating anticipated obstacles, perhaps to compensate for attention and motor deficits. These findings support the role of cognition in fall risk and the need to improve attention and cognition in fall prevention programs, especially among patients with more advanced disease.

Comparison of the Transcriptomic Signatures in Pediatric and Adult CML

Simple Summary

To investigate whether pediatric and adult chronic myeloid leukemia (CML) have unique molecular characteristics, we studied the transcriptomic signature of pediatric and adult CML cells using high-throughput RNA sequencing. We identified differentially expressed genes and pathways unique to pediatric CML cells compared to adult CML cells. The Rho pathway was significantly dysregulated in pediatric CML cells compared to adult CML cells, suggesting the potential importance in the pathogenesis of pediatric CML. Our study is the first to compare transcriptome profiles of CML across different age groups. A better understanding of the biology of CML across different ages may inform future treatment approaches.

Abstract

Children with chronic myeloid leukemia (CML) tend to present with higher white blood counts and larger spleens than adults with CML, suggesting that the biology of pediatric and adult CML may differ. To investigate whether pediatric and adult CML have unique molecular characteristics, we studied the transcriptomic signature of pediatric and adult CML CD34+ cells and healthy pediatric and adult CD34+ control cells. Using high-throughput RNA sequencing, we found 567 genes (207 up- and 360 downregulated) differentially expressed in pediatric CML CD34+ cells compared to pediatric healthy CD34+ cells. Directly comparing pediatric and adult CML CD34+ cells, 398 genes (258 up- and 140 downregulated), including many in the Rho pathway, were differentially expressed in pediatric CML CD34+ cells. Using RT-qPCR to verify differentially expressed genes, VAV2 and ARHGAP27 were significantly upregulated in adult CML CD34+ cells compared to pediatric CML CD34+ cells. NCF1, CYBB, and S100A8 were upregulated in adult CML CD34+ cells but not in pediatric CML CD34+ cells, compared to healthy controls. In contrast, DLC1 was significantly upregulated in pediatric CML CD34+ cells but not in adult CML CD34+ cells, compared to healthy controls. These results demonstrate unique molecular characteristics of pediatric CML, such as dysregulation of the Rho pathway, which may contribute to clinical differences between pediatric and adult patients.

Immunohistochemical ALK Expression in Granular Cell Atypical Fibroxanthoma: A Diagnostic Pitfall for ALK-Rearranged Non-neural Granular Cell Tumor

ABSTRACT

Atypical fibroxanthoma (AFX) is a neoplasm that most commonly occurs on sun-damaged skin of the head and neck in elderly patients and that usually exhibits indolent clinical behavior with complete excision. The granular cell variant of AFX demonstrates overlapping histopathologic features with dermal non-neural granular cell tumor (NNGCT), which typically arises on the extremities of young to middle aged adults with rare reports of regional metastasis. A subset of NNGCT harbors ALK rearrangements and expresses ALK by immunohistochemistry. Here, we present 2 cases of granular cell AFX occurring on the scalp of males aged 73 and 87 with ALK expression by immunohistochemistry and no evidence of an ALK rearrangement on fluorescence in situ hybridization, representing a diagnostic pitfall for NNGCT.

Which obstacle attributes place additional demands on higher-level cognitive function in patients with Parkinson's disease?

BACKGROUND

Previous reports show that patients with Parkinson's disease (PD) rely on prefrontal activation to compensate for impaired motor function during complex activities such as obstacle negotiation. However, the influence of the properties of the obstacles on prefrontal activation has not been systematically evaluated. Here, we examined the effects of obstacle height and anticipation time on prefrontal activation in patients with PD and older adults.

METHODS

34 patients with PD (age: 67.4 ± 5.7 years; 14 women) and 26 older adults (age: 71.3 ± 8.9 years; 11 women) walked in an obstacle course while negotiating anticipated and unanticipated obstacles (long/short available time response, ART) at heights of 50 mm and 100 mm. Prefrontal activation was measured using functional Near-Infrared Spectroscopy (fNIRS); obstacle negotiation performance was measured using Kinect cameras.

RESULTS

PD patients showed greater increases in prefrontal activation during and after obstacle crossing compared to the older adults (p < 0.001). Obstacle height affected prefrontal activity only when crossing anticipated obstacles (ARTxheight interaction, p = 0.011), in which case higher obstacles were accompanied by higher prefrontal activity. PD patients showed higher levels of activation during unanticipated obstacles, compared to older adults (groupXART: p = 0.015). Different correlations between prefrontal activation and obstacle negotiation strategies were observed in patients and controls.

CONCLUSIONS

These results point to the use of prefrontal activation as a compensatory mechanism in PD. Moreover, the higher activation observed when negotiating more challenging obstacles suggests that there is greater reliance on cognitive resources in these demanding situations that may contribute to the higher risk of falls in PD patients.

A multi-modal virtual reality treadmill intervention for enhancing mobility and cognitive function in people with multiple sclerosis: Protocol for a randomized controlled trial

BACKGROUND

Gait and cognitive impairments are common in individuals with Multiple Sclerosis (MS) and can interfere with everyday function. Those with MS have difficulties executing cognitive tasks and walking simultaneously, a reflection of dual-task interference. Therefore, dual-task training may improve functional ambulation. Additionally, using technology such as virtual reality can provide personalized rehabilitation while mimicking real-world environments. The purpose of this randomized controlled trial is to establish the benefits of a combined cognitive-motor virtual reality training on MS symptoms compared to conventional treadmill training.

METHODS

This study will be a single-blinded, two arm RCT with a six-week intervention period. 144 people with MS will be randomized into a treadmill training alone group or treadmill training with virtual reality group. Both groups will receive 18 sessions of training while walking on a treadmill, with the virtual reality group receiving feedback from the virtual system. Primary outcome measures include dual-task gait speed and information processing speed, which will be measured prior to training, one-week post-training, and three months following training.

DISCUSSION

This study will provide insight into the ability of a multi-modal cognitive-motor intervention to reduce dual-task cost and to enhance information processing speed in those with MS. This is one of the first studies that is powered to understand whether targeted dual-task training can improve MS symptoms and increase functional ambulation. We anticipate that those in the virtual reality group will have a significantly greater increase in dual-task gait speed and information processing speed than those achieved via treadmill training alone.

Nitrofurantoin-Induced Chronic Active Hepatitis In An Elderly Woman

A 78 year-old lady who received nitrofurantoin for two years developed chronic active hepatitis. In spite of withdrawal of Nitrofurantoin her condition continued to deteriorate, and a liver biopsy revealed severe chronic active hepatitis. She was treated by prednisone which resulted in improvement in her liver function tests and her general condition. However, two months later the patient developed a relapse of severe hepatitis with hepatic failure and she died in spite of treatment.

Severe hyponatraemia in elderly hospitalized patients: prevalence, aetiology and outcome

BACKGROUND

Hyponatraemia is the commonest electrolyte disorder in the elderly. Data on severe hyponatraemia and the prevalence of cerebral salt wasting syndrome (CSWS) in elderly hospitalized patients are lacking. We studied the incidence, frequency of various aetiologies, outcome and the possible role of CSWS in severe hyponatraemia in elderly medical patients.

METHODS

A prospective, observational, non-interventional study conducted over a 5-month period in medical wards. Eighty-six patients aged over 65 years with serum sodium levels < or =125 mEq/L were included. All patients were examined by one of the authors, who also evaluated potential contributing factors. Demographic, clinical and outcome data were extracted from the medical records.

RESULTS

The mean age of the patients was 82.1 + 8.7 years. The prevalence of hyponatraemia was 6.2% (8.1% women and 4.0% men (P < 0.001)). There was no increase in incidence of hyponatraemia with age. The leading cause of hyponatraemia was the syndrome of inappropriate antidiuretic hormone secretion (SIADH), whose aetiology could be determined in only 46% of cases. Aetiology was multifactorial in 51% of patients (1.7 aetiological factors per patient). All patients with thiazide-induced hyponatraemia had other contributing factors. Hyperglycaemia and hypoalbuminaemia were predictors of neurological manifestations of hyponatraemia. Overall in-hospital mortality was 19%. Only hypoalbuminaemia was found as an independent risk factor for death. In none of the patients was the hyponatraemia due to CSWS.

CONCLUSION

Severe hyponatraemia in elderly hospitalized medical patients is more frequent in women and of multifactorial aetiology in 50% of cases. It is most commonly caused by SIADH; CSWS is an unlikely cause.

Stable dicentric chromosomes induced by chemical mutagens in L5178Y mouse lymphoma cells

Stable, tandem dicentric chromosomes were discovered in two mutant cell colonies resulting from exposure of L5178Y mouse lymphoma cells to chemical mutagens. These unusual dicentrics were present in all metaphase cells examined from these colonies, even after approximately 65 cell generations in culture. Observation of cells in metaphase and anaphase suggests that the interstitial centromere in these dicentrics is non-functional, and that the terminal centromere is solely responsible for their orderly anaphase segregation.

Chromosome analysis of trifluorothymidine-resistant L5178Y mouse lymphoma cell colonies

Cells from small (sigma) and large (lambda) trifluorothymidine-resistant (TFTr) colonies induced by chemical mutagen treatment of TK+/-L5178Y mouse lymphoma cells were examined for chromosomal abnormalities. Analysis of G-banded metaphase chromosomes from 34 sigma-TFTr colonies revealed that cells from 20 (59%) possessed one or more chromosomal abnormalities. The most frequent (16/20 colonies) abnormality observed in cells from sigma-TFTr colonies involved the addition of extra chromatin to the distal region of one chromosome number 11. In 13 of these 16 colonies, the origin of the chromatin translocated to chromosome number 11 could not be identified; the chromatin was not missing elsewhere in the genome. The remaining three sigma-TFTr colonies with an abnormal chromosome number 11 had apparently whole chromosomes translocated, in tandem, to the distal region of chromosome number 11. Chromosomal abnormalities observed in cells from sigma-TFTr colonies with normal number 11 chromosomes included 2N/4N and 2N/4N/8N mosaicism (two colonies), a Robertsonian translocation involving chromosome 10 and a marker chromosome (one colony), and trisomy 7 (one colony). In most (14/16) sigma-TFTr colonies with structural damage to chromosome number 11, the cells within a colony were heterogeneous in that some possessed chromosomal damage whereas others were apparently normal. Analysis of chromosomes in cells from eight lambda-TFTr colonies revealed one colony in which all cells had a Robertsonian translocation involving chromosomes 1 and 16 plus other structural abnormalities. The chromosomes of cells from the remaining lambda-TFTr colonies were apparently normal.

Sister-chromatid exchange and cell replication kinetics in fetal and maternal cells after treatment with chemical teratogens

Effects of selected chemical teratogens on sister-chromatid exchange (SCE) frequencies and cell replication kinetics (CRK) in pregnant mice and their fetuses were investigated. Maternal and fetal cells were analyzed for SCE and classified as to whether they had gone through 1 (M1), 2 (M2), or 3 or more (M3+) cell cycles for quantifying cell replication kinetics and estimating average generation time (AGT). The teratogens tested in this system were mitomycin C (MMC), cyclophosphamide (CP), ethylnitrosourea (ENU), dimethylnitrosamine (DMN), lead acetate (LA), benzene (BEN), diethylstilbestrol (DES), diphenyldantoin (DPH), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and dimethyl sulfoxide (DMSO). MMC, CP, ENU, DMN, LA and BEN induced significant increases in SCE in both maternal and fetal cells compared with control values. DES and DPH induced increases in SCE in fetal cells only, whereas MNNG and DMSO did not induce any increase in SCE in either maternal or fetal cells. Chi-square analysis of the relative numbers of M1, M2 and M2+ cells revealed significant heterogeneity among test chemical doses in both maternal and fetal cells treated with all of the chemicals except DES. DES had an effect on fetal cells but not on maternal cells. A significant linear relationship between AGT and test chemical dose was noted for ENU and DMSO in maternal cells and DPH and MNNG in fetal cells. Although statistically significant, the effects of DPH, MNNG, and DMSO on AGT were small, with increases in AGT of only 1 h or less at the highest doses tested. ENU, however, resulted in more than a 2-h increase in the AGT of maternal cells. Average generation time was consistently lower in fetal cells as compared with maternal cells (overall mean AGT +/- S.D. from solvent controls was 8.6 +/- 0.3 h for fetal cells and 11.6 +/- 0.7 h for maternal cells). The results indicate that SCE induction and cell replication inhibition can occur independently, and that the assessment of SCE and CRK in maternal and fetal cells may be a promising approach to the identification of teratogenic agents.