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A method is described for cysteine (Cys) determination on paper-based analytical devices using aspartic acid modified gold nanoparticles (Asp-AuNPs). The Asp-AuNPs were characterized by their size, zeta potential, and UV-visible absorption spectrum. After the addition of Cys, it will interact with Asp-AuNPs selectively and leads to the aggregation of Asp-AuNPs. A color change from red to blue can be observed on the paper-based analytical devices. The results were recorded using a cell phone and subsequently analyzed using the Photoshop software. The ratiometric color intensity at red channel and blue channel (Red/Blue) increased linearly in the range 99.9-998.7 μM for Cys (R = 0.9984), and the limit of detection was 1.0 μM. The effects of assay conditions have been investigated and are discussed. The Cys concentration was determined as (0.27 ± 0.02 mM) in human plasma, and the recovery was from 99.2 to 101.1%. Graphical abstract Schematic representation of the paper-based assay system using aspartic acid modified gold nanoparticles (Asp-AuNPs). The ratiometric color intensity method was used for the cysteine (Cys) determination.

Heavy atom-chelated filter paper was synthesized and used as the substrate for room-temperature phosphorescence (RTP). The synthesis conditions for chelated paper were studied. The Pb-chelated filter paper could selectively induce the RTP of α-naphthalene acetic acid (α-NAA). The excitation and emission wavelengths of RTP of α-NAA were 300 nm and 521 nm, respectively. The concentration of α-NAA was linear with the RTP intensity in the range 2 × 10−6–6 × 10−4 mol/L (correlation coefficient, 0.9999). The concentration detection limit was 1.35 × 10−7 mol/L and the absolute detection limit was 0.25 ng/spot. The RSD (n = 10) was 1.7%. The method was applied to the analysis of water and vegetable samples with satisfactory results. Because the heavy atom was directly chelated onto the filter paper, the heavy-atom effect on the RTP of NAA was further increased and the analysis procedure was simple, fast and economical. Copyright © 2005 John Wiley & Sons, Ltd.

Following on our discovery that pulp and paper mill effluents can interact with, and disrupt, various neurotransmitter receptors and enzymes important to fish reproduction, we tested wood and bark extracts of 14 Eastern North American hardwood trees used in pulp and paper production. Radioligand binding to neurotransmitter receptors, including the dopamine-2 receptor (D2), the gamma aminobutyric acid receptor A (GABA(A)), N -methyl- d -aspartic acid (NMDA) receptor, and muscarinic cholinergic receptor (mACh-R), were significantly changed following in vitro incubations with many but not all extracts. Activities of neurotransmitter-related enzymes monoamine oxidase (MAO), GABA-transaminase (GABA-T), acetylcholinesterase (AChE) and glutamic acid decarboxylase (GAD) were also significantly altered. Butternut wood extracts and the isolated compound juglone significantly inhibited the enzymatic activities of MAO and GAD which we suggest may be part of a mechanism that may negatively affect fish reproduction. Besides giving credence to the hypothesis that neuroactive compounds in pulp and paper effluent may originate in the trees used by mills, the results reported here also indicate important neuropharmacological activities in hardwoods which may help identify new sources of biologically active natural products.

To determine the relationship of cerebral degeneration with survival in amyotrophic lateral sclerosis (ALS).Patients with probable or definite ALS underwent magnetic resonance spectroscopic imaging (MRSI) of the brain between July 1996 and May 2002, and were followed prospectively until March 2004. Creatine (Cr), choline (Cho) and the neuronal marker N-acetylaspartate (NAA) were quantified as ratios in the motor cortex.In 63 patients compared with 18 healthy people, NAA/Cho was reduced by 13% (p0.001), NAA/Cr was reduced by 5% (p = 0.01) and Cho/Cr was increased by 8% (p = 0.01). NAA/Cho was used for survival analysis, given its larger effect size and superior test accuracy (a sensitivity of 67% and a specificity of 83%). Median survival after MRSI was 24 months. Multivariate analysis showed reduced survival for lower NAA/Cho (hazard ratio (HR) 0.24, 95% confidence interval (CI) 0.08 to 0.72, p = 0.01), older age (HR 1.03, 95% CI 1.00 to 1.06, p = 0.04) and shorter symptom duration (HR 0.96, 95% CI 0.93 to 0.99, p = 0.01). Patients with NAA/Cho2.11 had a reduced survival of 19.4 v 31.9 months (HR 2.05, 95% CI 1.12 to 4.03, p = 0.02).Cerebral degeneration is predictive of reduced survival in ALS.

Background: Normal pressure hydrocephalus (NPH) is considered to be a treatable form of dementia, because cerebrospinal fluid (CSF) shunting can lessen symptoms. However, neuroimaging has failed to predict when shunting will be effective. Objective: To investigate whether 1 H (proton) magnetic resonance (MR) spectroscopy could predict functional outcome in patients after shunting. Methods: Neurological state including Hasegawa’s dementia scale, gait, continence, and the modified Rankin scale were evaluated in 21 patients with secondary NPH who underwent ventriculo-peritoneal shunting. Outcomes were measured postoperatively at one and 12 months and were classified as excellent, fair, or poor. MR spectra were obtained from left hemispheric white matter. Results: Significant preoperative differences in N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) were noted between patients with excellent and poor outcome at one month (p = 0.0014 and 0.0036, respectively). Multiple regression analysis linked higher preoperative NAA/Cr ratio, gait score, and modified Rankin scale to better one month outcome. Predictive value, sensitivity, and specificity for excellent outcome following shunting were 95.2%, 100%, and 87.5%. Multiple regression analysis indicated that NAA/Cho had the best predictive value for one year outcome (p = 0.0032); predictive value, sensitivity, and specificity were 89.5%, 90.0%, and 88.9%. Conclusions: MR spectroscopy predicted long term post-shunting outcomes in patients with secondary NPH, and it would be a useful assessment tool before lumbar drainage.

We performed (1)H-MR spectroscopy ((1)H-MRS) on multiple brain regions to determine the metabolite pattern and diagnostic utility of (1)H-MRS in multiple system atrophy (MSA).Examining single voxels at 3.0 T, we studied metabolic findings of the putamen, pontine base, and cerebral white matter in 24 MSA patients (predominant cerebellar ataxia (MSA-C), n = 13), parkinsonism (MSA-P), n = 11), in 11 age and duration matched Parkinson's disease patients (PD) and in 18 age matched control subjects.The N-acetylaspartate to creatine ratio (NAA/Cr) in MSA patients showed a significant reduction in the pontine base (p0.0001) and putamen (p = 0.02) compared with controls. NAA/Cr in cerebral white matter also tended to decline in long standing cases. NAA/Cr reduction in the pontine base was prominent in both MSA-P (p0.0001) and MSA-C (p0.0001), and putaminal NAA/Cr reduction was significant in MSA-P (p = 0.009). It was also significant in patients who were in an early phase of their disease, and in those who showed no ataxic symptoms or parkinsonism, or did not show any MRI abnormality of the "hot cross bun" sign or hyperintense putaminal rims. NAA/Cr in MSA-P patients was significantly reduced in the pontine base (p = 0.001) and putamen (p = 0.002) compared with PD patients. The combined (1)H-MRS in the putamen and pontine base served to distinguish patients with MSA-P from PD more clearly.(1)H-MRS showed widespread neuronal and axonal involvement in MSA. The NAA/Cr reduction in the pontine base proved highly informative in the early diagnosis of MSA prior to MRI changes and even before any clinical manifestation of symptoms.

Objectives: To determine whether proton magnetic resonance spectroscopy (MRS), a newer radiographic technology, would be useful in the evaluation of the thalamus of patients in vegetative states resulting from traumatic brain injury. Methods: 14 victims of severe traumatic brain injury who were in the vegetative state and whose magnetic resonance images of the thalamus were normal underwent bilateral thalamic proton (MRS) studies. The N-acetyl aspartate to creatine (NAA:Cr) and choline to creatine (Cho:Cr) ratios were obtained for each patient. The proton thalamic MRS findings of patients who were in a persistent vegetative state (n = 8) and in patients who had regained awareness after being in the vegetative state (n = 6) were compared with proton thalamic MRS findings in five healthy volunteers. Results: While conventional magnetic resonance imaging suggested that each patient had a normal thalamus, proton MRS indicated that the thalamus of each patient in the series was damaged. The NAA:Cr ratio was significantly lower in the thalami of both the patients who remained in a persistent vegetative state for the duration of the study and in those who regained awareness after being in the vegetative state (p < 0.001). In addition, NAA:Cr ratios were lower in the group of patients who remained in a persistent vegetative state than in the group of patients who regained awareness after being in the vegetative state (p < 0.001). Conclusions: Results suggest that the NAA:Cr ratio within the thalamus is significant and that thalamic MRS may be helpful when attempting to determine the degree of severity of neuronal and axonal injury in patients in the vegetative state.