Tau and 14-3-3 in glial cytoplasmic inclusions of multiple system atrophy

Multiple system atrophy (MSA) is a neurodegenerative disease characterized by the presence of glial cytoplasmic inclusions (GCIs), which are comprised of fibrils of the protein -synuclein (-syn). Increasing evidence indicate that the formation of these lesions leads to cellular dysfunction and degeneration. The events that result in the formation of GCIs remain poorly understood. It is possible that changes in the cytoplasmic milieu, perhaps the aberrant expression of -syn-interacting proteins, can promote the polymerization of -syn. The presence of the microtubule-binding protein, tau, in GCIs has been reported in some studies, but these findings have not been consistent, and these studies were performed prior to the availability of the more sensitive methods of detecting GCIs using anti--syn antibodies. Recently, 14-3-3 proteins, putative -syn-interacting partners, have been reported in Lewy bodies, which also are pathological inclusions comprised of -syn. In this study the presence of tau and 14-3-3 proteins in GCIs of 21 patients with MSA was investigated. For the majority of cases, tau and 14-3-3 proteins were detected only in a subset of GCIs. In some cases none of the GCIs contained 14-3-3 or tau. When present in GCIs, tau was in a hypophosphorylated state as demonstrated with phosphorylation-specific antibodies. -syn fibrillogenesis without 14-3-3 or tau appears to be sufficient for GCI formation, although it is possible that the accumulation of multi-functional proteins, like 14-3-3, in GCIs contribute to the disruption of cellular homeostasis.     

A disease-specific psychosocial questionnaire for Parkinson’s disease caregivers

Abstract. Objective: To evaluate the Belastungsfragebogen Parkinson Angehörigen—kurzversion (BELA-A-k), a questionnaire for measuring psychosocial problems and need for help in Parkinsons disease (PD) caregivers. Methods: The Belastungsfragebogen Parkinson Angehörigen—kurzversion was translated into Dutch. It consists of 15 items with a Bothered by (Bb) and a Need for Help (NfH) score. The BELA-A-k was tested for cultural differences, relevance and feasibility in a pilot (n = 10). We determined the psychometric properties in a validation study (n = 50) and compared the BELA-A-k with the Sickness Impact Profile, the COOP/WONCA Functional Health Assessment Charts and the Loneliness Questionnaire (de Jong-Gierveld). All questionnaires were administered in person at home, in a prescribed order. Results: The BELA-A-k was completed by 60 PD-caregivers. The internal-consistency reliability coefficients for the total Bothered by (0.90) and Need for Help (0.92) scales were excellent. The internal consistency of the subscales exceeded the 0.70 standard except for the Bothered by and Need for Help Social functioning scale (Bb = 0.62; NfH = 0.65) and the Partner-bonding/Family scale (NfH = 0.69). Almost all BELA-A-k subscales correlated highly (P < 0.001) with the corresponding scales of the standard quality of life indices. Conclusion: The BELA-A-k is a relevant, reliable and valid measure for assessing psychosocial problems and need for help of PDcaregivers.     

Alzheimer's peptide and serine proteinase inhibitors in glaucoma and exfoliation syndrome

The occurrence of inflammation with accompanying amyloid formation in pseudoexfoliation syndrome (PEX) resembles other inflammation-associated amyloidoses such as Alzheimer's disease (AD). To test whether the same proteins can be identified in PEX as in AD, we qualitatively analysed for Alzheimer's peptide (A_1-42) and the proteinase inhibitors ₁-antichymotrypsin (ACT) and ₁-antitrypsin (AAT) in the aqueous humor of patients with and without PEX material. Ninety aqueous humor samples were collected from patients in the age group between 46 and 95 during cataract surgery. Protein profiles in samples were analysed by electrophoresis followed by Western blotting. Blots were developed using specific antibodies against A_1-42, AAT and ACT and peroxidase-conjugated IgG as a second antibody. At least one of the analysed proteins was found in 68.8% of 90 cases studied. A_1-42 peptide was found in 22.2% of all cases, among them in seven cases with PEX (total n=16) and in four with glaucoma (total n=10). ACT and AAT were detected in 17.8 and 28.9% of all cases, respectively. In addition, female patients had significantly higher frequencies of detected ACT and AAT, compared to males. A_1-42, ACT and AAT were also found in 17.6, 14.7 and 23.5% of the control (non-XF and non-glaucoma) samples (n=68). Alzheimer's peptide is present in the aqueous humor of patients with PEX and glaucoma suggesting that these diseases may share common features in the biochemistry and etiologies with AD. The presence of A and inflammation-associated proteins in aqueous from cataract cases without detectable PEX raises the possibility that these proteins may reflect early amyloid-related changes in the eye.     

Degradation of endomorphin-2 at the supraspinal level in mice is initiated by dipeptidyl peptidase IV: an in vitro and in vivo study

Endomorphin-2 (Tyr-Pro-Phe-PheNH(2)) was discovered as an endogenous ligand for the mu-opioid receptor. The physiological function of endomorphin-2 as a neurotransmitter or neuromodulator may cease through the rapid enzymatic process in the synapse of brain, as for other neuropeptides. The present study was conducted to examine the metabolism of endomorphin-2 by synaptic membranes prepared from mouse brain. Major metabolites were free tyrosine, free phenylalanine, Tyr-Pro and PheNH(2). Both the degradation of endomorphin-2 and the accumulation of major metabolites were inhibited by specific inhibitors of dipeptidyl peptidase IV, such as diprotin A and B. On the other hand, the accumulation of Phe-PheNH(2) and Pro-Phe-PheNH(2) was increased in the presence of bestatin, an aminopeptidase inhibitor, whereas that of free phenylalanine and PheNH(2) was decreased. Furthermore, purified dipeptidyl peptidase IV hydrolyzed endomorphin-2 at the cleavage site, Pro(2)-Phe(3) bond. Thus, degradation of endomorphin-2 by brain synaptic membranes seems to take place mainly through the cleavage of Pro(2)-Phe(3) bond by dipeptidyl peptidase IV, followed by release of free phenylalanine and PheNH(2) from the liberated fragment, Phe-PheNH(2) by aminopeptidase. We have also examined that the effect of diprotin A on the antinociception induced by intracerebroventricularly administered endomorphin-2 in the mouse paw withdrawal test. Diprotin A simultaneously injected with endomorphin-2 enhanced endomorphin-2-induced antinociception. These results indicate that dipeptidyl peptidase IV may be an important peptidase responsible for terminating endomorphin-2-induced antinociception at the supraspinal level in mice.     

Inhibition of dipeptidyl peptidase I in the human mast cell line HMC-1: blocked activation of tryptase, but not of the predominant chymotryptic activity

The mast cell proteases tryptase and chymase are synthesised as inactive precursors, but are stored and secreted as active enzymes. The cysteinyl protease dipeptidyl peptidase I (DPPI, cathepsin C) can activate the corresponding proenzymes in cell-free systems, but it is unknown whether it fulfils this role within the intact cell. We, therefore, tested the effect the DPPI-selective inhibitor Gly-Phe diazomethyl ketone (Gly-Phe-CHN(2)) on the tryptic and chymotryptic activity of the human mast cell-like cell line, HMC-1, and monitored any changes in the amount of immunodetectable enzymes by flow cytometry. Culture in Gly-Phe-CHN(2) produced a significant decrease in tryptase activity in cell lysates within 24hr and further decreases during continued culturing to 216 hr with periodic replenishment of Gly-Phe-CHN(2)-containing media. Flow cytometry showed no significant change in the levels of immunoreactive tryptase. In contrast, chymotryptic activity in treated cells did not differ significantly from untreated cells at any time point. Treatment of 216 hr cell lysates with DPPI revealed significant amounts of activatable protryptase in Gly-Phe-CHN(2)-treated cells, but not in controls, whereas activatable prochymotryptic activity was found in both treated and control cells. Chymase was detected immunologically, though small differences in substrate specificity and molecular mass were observed. These results strongly suggest that DPPI plays a role in the activation of tryptase, but not of the predominant chymotryptic activity of HMC-1 cells. As inhibitors of tryptase have proven efficacious in models of allergic disease, these results also indicate that inhibitors of DPPI might provide an additional point of therapeutic control.     

Comparison of Alaris AEP index and bispectral index during propofol-remifentanil anaesthesia

Background. The Alaris AEP monitor^TM (Alaris, UK, version 1.4)is the first commercially available auditory evoked potential(AEP) monitor designed to estimate the depth of anaesthesia.It generates an ‘Alaris AEP index’ (AAI), whichis a dimensionless number scaled from 100 (awake) to 0. Thisstudy was designed to compare AAI and BIS^TM (Aspect, USA, versionXP) values at different levels of anaesthesia. Methods. Adult female patients were premedicated with diazepam0.15 mg kg^–1 orally on the morning of surgery. Electrodesfor BIS and Alaris AEP monitoring and a headphone to give auditorystimuli were applied as recommended by the manufacturers. Anaesthesiawas induced with remifentanil (0.4 µg kg^–1 min^–1)and a propofol target-controlled infusion (Diprifusor^TM TCI,AstraZeneca, Germany) to obtain a predicted concentration ofinitially 3.5 µg ml^–1. After loss of consciousnessthe patients were given 0.5 mg kg^–1 of atracurium. Aftertracheal intubation, remifentanil was given at 0.2 µgkg^–1 min^–1 and the propofol infusion was adjustedto obtain BIS target values of 30, 40, 50, and 60. AAI and BISvalues were recorded and matched with the predicted propofoleffect-site concentrations. Prediction probability was calculatedfor consciousness vs unconsciousness. Values are mean (SD). Results. Fifty female patients, 53 (15), range 18–78 yr,ASA I or II were studied. Mean values before induction of anaesthesiawere 95 (4), range 99–82 for BIS and 85 (12), range 99–55for AAI. With loss of eyelash reflex both values were significantlyreduced to 64 (13), range 83–39 for BIS (P<0.05) and61 (22), range 99–15 for AAI (P<0.05). The predictionprobability P_K for consciousness vs unconsciousness (i.e. lossof eyelash reflex) was better for BIS (P_K=0.99) than for AAI(P_K=0.79). At a BIS of 30, 40, 50, and 60 the correspondingAAI values were 15 (6), 20 (8), 28 (11), and 40 (16), and thesewere significantly different. Conclusions. During propofol-remifentanil anaesthesia a decreaseof the depth of anaesthesia as indicated by BIS monitoring isaccompanied by corresponding effects shown by the AAI. However,wide variation in the awake values and considerable overlapof AAI values between consciousness and unconsciousness, suggestsfurther improvement of the AAI system is required. Br J Anaesth 2003; 91: 336–40     

Closed-loop control of propofol anaesthesia using bispectral index: performance assessment in patients receiving computer-controlled propofol and manually controlled remifentanil infusions for minor surgery

Background. In a previous study we used the bispectral index(BIS)^TM for automatic control of propofol anaesthesia, usinga proportional-integral-differential control algorithm. As controlwas less than optimal in some patients, we revised the constantsof the control algorithm. The aim of the current study was tomeasure the performance of the revised system in patients undergoingminor surgery under propofol and remifentanil anaesthesia. Methods. Twenty adult patients scheduled for body surface surgerywere enrolled. Anaesthesia was manually induced with target-controlledinfusions (TCI) of propofol and remifentanil. After the startof surgery, when anaesthesia was clinically adequate, automaticcontrol of the propofol TCI was commenced using the revisedclosed-loop system. For patients 11–20, effect-site steeringwas also incorporated into the closed-loop control algorithm.Adequacy of anaesthesia during closed-loop control was assessedclinically, and by calculating the median performance error(MDPE), the median absolute performance error (MDAPE) and themean offset of the control variable. Results. The system provided adequate operating conditions andstable cardiovascular values in all patients during closed-loopcontrol. The mean MDPE and MDAPE were –0.42% and 5.63%,respectively. Mean offset of the BIS^TM from setpoint was –0.2.No patients reported awareness or recall of intraoperative events. Conclusions. The system was able to provide clinically adequateanaesthesia in all patients, with better accuracy of controlthan in the previous study. There was a tendency for more accuratecontrol in those patients in whom the control algorithm incorporatedeffect-site steering. Br J Anaesth 2003; 90: 737–41     

Propofol 1% versus propofol 2% in children undergoing minor ENT surgery

Background. The induction characteristics of propofol 1% and2% were compared in children undergoing ENT surgery, in a prospective,randomized, double-blind study. Methods. One hundred and eight children received propofol 1%(n=55) or 2% (n=53) for induction and maintenance of anaesthesia.For induction, propofol 4 mg kg^–1 was injectedat a constant rate (1200 ml h^–1), supplementedwith alfentanil. Intubating conditions without the use of aneuromuscular blocking agent were scored. Results. Pain on injection occurred in 9% and 21% of patientsafter propofol 1% and 2%, respectively (P=0.09). Loss of consciousnesswas more rapid with propofol 2% compared with propofol 1% (47 svs 54 s; P=0.02). Spontaneous movements during inductionoccurred in 22% and 34% (P=0.18), and intubating conditionswere satisfactory in 87% and 96% (P=0.19) of children receivingpropofol 1% or 2%, respectively. There were no differences betweenthe two groups in respect of haemodynamic changes or adverseevents. Conclusions. For the end-points tested, propofol 1% and propofol2% are similar for induction of anaesthesia in children undergoingminor ENT surgery. Br J Anaesth 2003: 90: 375–7     

Implicit memory formation in sedated ICU patients after cardiac surgery

Background. Recent research into memory formation under sedationhas generated conflicting results. We investigated explicitand implicit memory in ICU patients during moderate to deeppropofol sedation following cardiac surgery. Methods. Two different methods of memory testing were used;(1) free-association (F-A) word-pair testing (n=33) to testconceptual implicit memory and (2) process dissociation procedure(PDP) (n=26) to detect perceptual implicit and explicit memory.One hour after surgery, whilst sedated, the F-A group receivedone of two lists of 10 category-exemplar word-pairs throughheadphones, while the PDP group was presented with one of twolists of 16 five-letter words. When awake and co-operative,the F-A group was tested using F-A testing, and the PDP groupwas tested using the PDP. Results. The F-A group had a mean (SD) correct response rateof 7 (9)% for the target list, and 9 (8)% for the distractorlist. The PDP group had a mean (SD) correct response rate of11 (14) and 10 (13)% for the inclusion and exclusion lists,respectively, with mean correct response rates of 13 (14)% forboth the corresponding distractor lists. Neither group showedany significant differences between their responses and a listof distractor words (Wilcoxon tests). Conclusion. We found no evidence for memory formation in post-cardiacsurgery patients under moderate to deep propofol sedation. Br J Anaesth 2003; 91: 810–14