Ubiquitin binds the amyloid β peptide and interferes with its clearance pathways

Several lines of evidence point to a compromised proteostasis associated with a reduction of the Ubiquitin Proteasome System (UPS) activity in patients affected by Alzheimer's Disease (AD) and suggest that the amyloid β peptide (Aβ) is an important player in the game. Inspired also by many reports, underlining the presence of ubiquitin (Ub) in the amyloid plaques of AD brains, here we set out to test whether Ub may bind the Aβ peptide and have any effect on its clearance pathways. By using an integrated array of MALDI-TOF/UPLC-HRMS, fluorescence, NMR, SPR, Microscale Thermophoresis (MST) and molecular dynamics studies, we consistently demonstrated that Aβ40 binds Ub with a 1 : 1 stoichiometry and K d in the high micromolar range. In particular, we show that the N-terminal domain of the Aβ peptide (through residues D1, E3 and R5) interacts with the C-terminal tail of Ub (involving residues K63 and E64), inducing the central region of Aβ (14HQKLVFFAEDVGSNK28) to adopt a mixed α-helix/β-turn structure. ELISA assays, carried out in neuroblastoma cell lysates, suggest that Aβ competitively binds Ub also in the presence of the entire pool of cytosolic Ub binding proteins. Ub-bound Aβ has a lower tendency to aggregate into amyloid-like fibrils and is more slowly degraded by the Insulin Degrading Enzyme (IDE). Finally, we observe that the water soluble fragment Aβ1-16 significantly inhibits Ub chain growth reactions. These results evidence how the non-covalent interaction between Aβ peptides and Ub may have relevant effects on the regulation of the upstream events of the UPS and pave the way to future in vivo studies addressing the role played by Aβ peptide in the malfunction of proteome maintenance occurring in AD.

Evaluation of Bone Mineral Density in Patients with Type 1 Gaucher Disease in Argentina

The purpose of this study was to evaluate the frequency of osteoporosis (OP) in patients with Gaucher disease (GD) in Argentina. GD patients from 28 centers were consecutively included from April 2012 to 2014. Bone mineral density (BMD) was determined by dual X-ray absorptiometry in the lumbar spine and the femoral neck or the total proximal femur for patients ≥20 yr of age, and by whole-body scan in the lumbar spine in patients <20 yr of age. In children, mineral density was calculated using the chronological age and Z height. OP diagnosis was determined following adult and pediatric official position of the International Society for Clinical Densitometry. A total of 116 patients were included, of which 62 (53.5%) were women. The median age was 25.8 yr. All patients received enzyme replacement therapy, with a median time of 9.4 yr. Normal BMD was found in 89 patients (76.7%), whereas low bone mass (LBM) or osteopenia was found in 15 patients (13%) and OP in 12 patients (10.3%). The analysis of the pediatric population revealed that 4 patients (9.3%) had LBM and 3 (7%) had OP (Z-score ≤ -2 + fractures height-adjusted by Z), whereas in the adult population (n = 73), 11 patients (15%) had LBM or osteopenia and 9 (12.3%) had OP. Bone marrow infiltration and the presence of fractures were significantly correlated with the presence of OP (p = 0.04 and <0.001, respectively). This is the first study in Argentina and in the region describing the frequency of OP or LBM in GD patients treated with imiglucerase using the official position of the International Society for Clinical Densitometry.

The insulin degrading enzyme activates ubiquitin and promotes the formation of K48 and K63 diubiquitin

We report an ATP-dependent ubiquitin conjugation with IDE which, in turn, promotes Ub-Ub linkages in tube tests. We propose a novel function for IDE as a non-canonical ubiquitin activating enzyme.

Emerging dynamics in neuronal networks of diffusively coupled hard oscillators

Oscillatory networks are a special class of neural networks where each neuron exhibits time periodic behavior. They represent bio-inspired architectures which can be exploited to model biological processes such as the binding problem and selective attention. In this paper we investigate the dynamics of networks whose neurons are hard oscillators, namely they exhibit the coexistence of different stable attractors. We consider a constant external stimulus applied to each neuron, which influences the neuron's own natural frequency. We show that, due to the interaction between different kinds of attractors, as well as between attractors and repellors, new interesting dynamics arises, in the form of synchronous oscillations of various amplitudes. We also show that neurons subject to different stimuli are able to synchronize if their couplings are strong enough.

Conversion of spinal anesthesia into general anesthesia: an evaluation of more than 35,000 spinal anesthetics

BACKGROUND

The aim of this study was to evaluate the number of conversions from spinal anesthesia (SA) into general anesthesia (GA) in a large number of patients who underwent surgery over a period of twenty-one years.

METHODS

From the hospital's database, all surgical procedures performed under SA between January 1, 1988 and December 31, 2008 were retrieved. From this file, all SA cases converted into GA cases requiring endotracheal intubation were selected. Patients were divided in four groups, according to the reason for GA: IMPOSS (SA impossible to perform), FAIL (SA non profound enough for allowing surgery, even with light sedation), INSUFF (SA inadequate for unexpected prolonged duration of surgery), and COMPL (occurrence of complications associated with SA and requiring rapid control of ventilation). Anesthesiologists who performed SA were divided according their experience. The outcomes of patients converted to GA were compared with a matched sample of patients who received planned GA.

RESULTS

A total of 35,960 SA cases were performed from 1988 to 2008; 29,220 and 6,740 SA cases were for elective and emergency surgery, respectively. Two hundred seventeen (0.6%) SA cases were converted into GA cases; 80.2% and 19.8% of the conversions were recorded in elective and emergency operations, respectively, with obstetric operations being the most prevalent (82/217). The primary reasons for the conversions, in a rank order, were INSUFF 107 (49.3%), FAIL 84 (38.7%), IMPOSS 13 (5.9%), and COMPL 13 (5.9%). Complications more frequently occurred in the aged population (P<0.05). Anesthesiologists with less experience had higher percentages of FAIL, IMPOSS, INSUFF, and COMPL SA cases in comparison with experienced anesthesiologists (odd ratios being 4.7, 3.0, 2.4, and 4.4, respectively). There was no difference in the frequency of complications compared to a matched sample of 1,000 patients who underwent GA (P=0.65).

CONCLUSION

SA has been found to be a safe and highly effective technique. Failure of SA was infrequent in a large number of patients surveyed and most often occurred with less experienced anesthesiologists. Conversion to GA did not produced different outcomes in comparison with planned GA. Prospective studies with a definite protocol for recording data performed on a large number of patients may help in determining the factors associated with conversion from SA into GA and how to avoid these unexpected situations.

Refeeding syndrome in early pregnancy. Case report

Refeeding syndrome is a very serious disorder that is not often observed today, as it is more common during times of mass starvation or war. Nowadays, it is sometimes found in patients suffering from anorexia nervosa or neoplastic diseases. A case recently treated in our Intensive Care Unit is described. The patient was pregnant and suffering from Crohn's disease. It is emphasized that although refeeding syndrome is often fatal if not treated early, it is easily prevented or treated with adequate nutritional support.

[Assessment of operating theatre procedures and quality of perioperative anaesthesia using a computer system for collecting anaesthesiological data]

BACKGROUND

In order to manage the operating theatre and guarantee constant improvement in the quality of procedures, it is indispensable to be able to have available a computerised workstation to enable the team to collect data and analyse them.

METHODS

We used our anaesthesia department's computer workstation to retrospectively analyse operating sessions over a 16 month period during which organisational adjustments were made to optimise patient turnover and maximise the utilisation of operating theatres. Meantime we studied and compared the trend in anaesthesiological quality through the use of certain structural, process and outcome indicators.

RESULTS

During the period under study an improvement was noted in the efficiency of operating theatre procedures (reduction in entry time of the first patient into the theatre, time between one case and the next and subutilisation of the operating theatre, p<0.05). As regards data on the quality of anaesthesiological assistance to the patient, no significant differences were noted when comparing the four periods examined.

CONCLUSIONS

To make the operating complex work more efficiently, it is necessary to have available a computer system that makes it possible to continuously monitor theatre operation. The improvement initiatives undertaken led to a more effective utilisation of the operating theatre but did not produce a significant increase in productivity. In spite of the increased work load, analysis of the trend in quality indicators as regards anaesthesiological procedures did not reveal any modification.

Automatic record keeping in anaesthesia--a nine-year Italian experience

In 1986, in Buccheri La Ferla Hospital, Palermo, an anaesthesia information management project was started. Its aim was to develop a computerized anaesthesia workstation. Today, the system is in daily clinical use and has reached most of its original goals: Automatic collection of physiological signals and patient monitor trends is possible by means of analog-digital conversion or by using serial data transfer. A centralized display is included in the system to allow easy control of the progress of the anaesthetic procedures in the hospital. Available in the workstation, there is an on-line help function to assist pharmacological calculations and administration of anaesthesia drugs. Mail messages can be sent to different anaesthesia workstations and data can be shared between them. Information collected during preoperative visits is automatically transferred from a portable personal computer to the system. There is a nine-year patient data-base with both preoperative and perioperative anaesthesia information which can be accessed from each of the workstations. Today, the system is in daily routine use and comprises eight anaesthesia workstations and two portable personal computers used for preoperative visits. The operation schedule with anaesthetists' notes is printed both for surgical wards and for O.R., using information stored from preoperative visits to the system. For automated data collection a trend resolution of one minute has been used. The postoperative orders are printed from the system in the recovery room and given to the wards with the patient. The feedback from the seventeen anaesthetists and twenty-four nurses who use the system routinely is positive. Today, 16,000 patient records are available in the database. This number increases by 3,300 every year. With increasing computer utilization in patient treatment there have been no legal or administrative controversies. Based on nine years' experience, it is clear that the use of computers in anaesthesia practice improves quality of patient care.

[The use of dobutamine during the intraoperative period to prevent organ hypoperfusion in non-heart surgery. Administration modality and monitoring]

Dobutamine is strongly recommended in the treatment of critical intensive care patients in order to improve cardiac performance and peripheral perfusion. In non-cardiac surgery there are frequent cases of organ hypoperfusion that could be treated with dobutamine; the drug, however, is not advocated since it is difficult to control without invasive hemodynamic monitoring. This study analyzed the possibilities of using and controlling dobutamine in non-cardiac surgery. The study covered 186 patients ranging from 40 to 80 years of age who were divided into two groups according to ASA class and the type of surgery they were to undergo (Group I ASA 1-2 major surgery, group 2 ASA 3-4 standard and major surgery). Of these, 93 patients were treated with dobutamine infusion, 3 mu/kg/min, started before anesthesia and modulated for the duration of the operation on the basis of the patient's monitoring values. The remaining 93 patients were the controls who underwent the same anesthesiological procedure without receiving the drug. During anesthesia we monitored: mean blood pressure, pulsioxiometry, fraction of exhaled CO2 and heart rate. Analyses were done using a personal computer network connected to the patient monitoring system. For each parameter we calculated the number of times per hour of anesthesia that different readings were taken (higher or lower) with respect to the value recorded immediately after premedication. The following variations were considered significant. 5 mmHg for blood pressure, 10 b/min for heart rate, 4% higher or lower for exhaled CO2; plus or minus 95% for pulsioximetry. The data were evaluated using the chi 2 test. The treated patients showed significantly higher blood pressure, exhaled CO2 and heart rate values, demonstrating that dobutamine infusion can be piloted on the basis of these monitoring parameters. The treated patients had 4% higher exhaled CO2 levels showing the close correlation between exhaled CO2 and the use of the inotrope. The overall results show that dobutamine is easy to use and readily piloted during anesthesia for non-cardiac surgery.

[In vitro and in vivo effects of propofol on the hemoglobin dissociation curve]

This study assessed in vivo and in vitro the effects of propofol on the affinity of hemoglobin for oxygen in seven ASA 1 adults. For the in vivo study, venous blood samples were withdrawn before and after premedication, after the injection of 2.5 mg.kg-1 of propofol and after 15 minutes of maintenance at an infusion rate of 0.2 mg.kg-1.min-1. For the in vitro study, propofol was added to the blood withdrawn before premedication in order to obtain two samples at a concentration of 1 microgram.mL-1 and 2 micrograms.mL-1 respectively. Propofol changed neither in vivo, nor in vitro, the P50 and the number of Hill indicating the angle of the slope of the dissociation curve, nor in vivo the concentration of 2,3-DPG.

Informatics in palliative care

A computerized documentation system for palliative care would allow immediate availability of patient data and rapid evaluation of treatment. To develop such a system, many problems must be resolved, including choice of data and type of display. A preliminary screening of information and the introduction of codes to show some parameters are necessary to achieve a good result. We describe a program that allows data entry, storage of data, rapid display and printout of data, and recording of history, previous therapy, pathologic, physical, and laboratory findings, diagnosis, mechanisms and site of pain, drugs, and symptoms. Further improvements and problems are discussed.

The effect of N2O on the oxyhemoglobin dissociation curve is mediated by CO2

In order to test whether the previously reported effect of N2O on the oxyhemoglobin dissociation curve (ODC) depends upon the presence of 2, 3 DPG or CO2, the blood of healthy subjects was balanced in microtonometers at 37 degrees C with gas mixtures containing N2O but CO2 depleted. Samples of the same blood were exposed to the above gases after incubation at 37 degrees C for 24 hours in order to deplete them of 2, 3 DPG. After a 10 minute tonometry, the hemoglobin saturation and the pH were measured. The pH was corrected into 7.4.P50 increased 5.7% in fresh blood and 5% in 2, 3 DPG depleted blood after samples exposure to N2O. No effect of N2O on P50 was found in samples exposed to gas without CO2. The authors conclude that the effect of N2O on the ODC is mediated by CO2.

[Importance of an outpatient record in obstetric anesthesia]

A computerised record was used to collect data following an anesthesiological check-up of pregnant women at approximately 30 weeks of pregnancy. The record was input onto a portable PC in the anesthesia outpatient clinic, memorized on disk (3.5") and then transferred onto a PC network (one PC for each operating theatre) for "real time" consultation of each patient's data. All pregnant women attending the antenatal clinico were also given a folder illustrating epidural anesthetic techniques. Seven hundred and nine outpatient visits have been performed over the past two years with a 62% utilisation ratio. The collection of data using a computerised system allows a rapid and efficacious system of communication to be set up among the membranes of the anesthesiological team, thus encouraging the use of epidural techniques during labour. The distribution of the folder also facilitated the task of the anesthetist who found that pregnant women visiting the anesthesia clinic were already familiar with the epidural technique.

GATA repeats in the genome of Asellus aquaticus (Crustacea, Isopoda)

A 500 bp fragment of Drosophila genomic DNA containing 37 copies of the tetranucleotide GATA was used to probe, by Southern DNA blotting and in situ hybridization, two natural populations of the isopod crustacean Asellus aquaticus collected from the Sarno and Tiber rivers. This species does not have a recognizable sex chromosome pair. In a number of males from the Sarno population chromomycin A3 staining reveals a heteromorphic chromosome pair. The heterochromosome has two blocks of heterochromatin. After digestion of genomic DNA with six restriction endonucleases and hybridization with the GATA probe, the two populations exhibit different fragment length patterns. No sex-linked pattern was observed in either population. In situ hybridization to chromosomes of males and females from the Sarno population does not reveal any sex-specific pattern of labelling and indicates a scattered distribution of GATA sequences on most chromosomes with some areas of preferential concentration. The heterochromatic areas of the male heterochromosome are not labelled.

[Continuous infusion peridural analgesia in labor]

A technique of continuous infusion epidural anesthesia was used during labour in 933 patients divided into three groups according to age: Group A (14-18 years old), Group B (19-35 years old) and Group C (greater than 35 years old). Infusion was carried out using the following system: a PVC pressurized bag containing 0.3% marcain connected to 2 flow regulators which ensured a flow of 6 ml/h. During the dilatation phase, 85% of patients received sufficient analgesia, whereas 15% required extra boluses. During the expulsive phase 80% of patients received adequate analgesia of the perineal plane, 12% received an extra bolus of marcain 0.3% and local anesthesia was performed in 8% to allow infiltration. Instruments were required in 5.6% of patients in Group A, 11.3% in Group B and 7.4% in Group C. The incidence of Caesarian section was 5.6% in Group A, 9% in Group B and 14.8% in Group C. No maternal complication was observed. Epidural anesthesia via continuous infusion was therefore shown to be an efficacious and safe method for ensuring analgesia during labour.

[Evaluation of the liberation of urinary necrosis enzymes (NAG-AAP) after administration of plasma expanders: study of dextran 40, hydroxyethyl starch and polymerized gelatin]

We studied the 24-hour urinary elimination of enzymatic markers of renal tubular necrosis (NAG-AAP) in 21 patients (mean age 34.6 years old) who were treated with plasma expanders before peridural anesthesia. The patients were divided into three groups of seven subjects each: - 14 ml/Kg -1 of dextran 40 was administered to group 1 - 14 ml/Kg -1 of gelatin was administered to group 2 - 14 ml/Kg -1 of hydroxyethyl starch was administered to group 3. Urinary elimination of N-acetylglucosaminidase and of alanine aminopeptidase was determined in the 24-hour urine the day before surgery (controls), the day of surgery (G1) and the day after surgery (G2). The values of the samples, taken after plasma expander administration, did differ significantly from the control values (G1, G2). Therefore the administration of 14 ml/Kg -1 of dextran, gelatin or hydroxyethyl starch does not affect the renal tubular epithelium.

Effects of halothane, enflurane, and nitrous oxide on oxyhemoglobin affinity

To test whether anesthetics alter hemoglobin O2 affinity, venous blood was sampled from 27 healthy subjects before and during general anesthesia for appendectomy with halothane, enflurane, or nitrous oxide anesthesia. 0.110-ml aliquots of blood were equilibrated in microtonometers at 37 degrees C with known PO2 levels in gases containing 0%, 0.5%, 1%, 2%, or 3% halothane, 0%, 1%, 2%, 3%, or 4% enflurane, or 60% N2O. pH was then measured and PO2 corrected to pH = 7.4. Saturation was determined spectrophotometrically (Radiometer OSM-2). P50 computed from this PO2 and measured saturation was increased 5% (P less than 0.01) when blood was tonometered with N2O, but not in blood samples taken during N2O anesthesia and then equilibrated without N2O. Halothane and enflurane had no effect. 2,3 DPG was not affected by any agent. The authors conclude that inhalational agents in use today do not cause the oxygen dissociation curve to change in a way which might jeopardize the patient's oxygenation.

Hemodynamics, prolactin and catecholamine levels during hemorrhagic shock in dogs pretreated with a prolactin inhibitor (bromocriptine)

Bromocriptin, a dopaminomimetic drug, causing inhibition of prolactin secretion, was used in experiments on haemorrhagic shock in dogs. 5 dogs were treated with bromocriptine (0.4 mg.day-1) for two days; a further 5 dogs were used as control animals. 30% of the blood volume was drawn from each dog. Mean arterial blood pressure, heart rate, central venous pressure, acid-base status, prolactin, GH and catecholamine levels were checked before blood letting and monitored until 1 hour after blood letting. Animals treated with bromocriptine showed a significant decrease of the mean arterial blood pressure and of the prolactin rate and a significant increase of catecholamine levels. Control animals, instead, showed a significant increase of the prolactine and catecholamine rates. The results obtained suggest that bromocriptine can constitute an additional hypotensive factor in subjects with acute haemorrhage. A considerable amount of research work previously carried out has shown a close correlation between stress and hyper-prolactinemia. The increase of prolactinemia and the effects of bromocriptine on this hormone during surgical stress is particularly interesting due to its possible implications (Lanza V. et coll., 1983). In previous experiments involving animals it was found that Prolactin exerts positive chronotropic and hypertensive effects (Horrobin D.F., 1977) whilst bromocriptine is a potent agonist of D2 dopaminergic receptors (Thorner M.O. et coll., 1980). Dopamine was found to be particularly useful in the clinical treatment of shock thus suggesting an involvement of peripheral D2 receptors. On the basis of these observations we have considered it worthwhile to investigate the haemodynamic effects of bromocriptine in haemorrhagic shock.

[Neuroendocrine response to anesthesia with isoflurane]

The effects during surgery of a new halogenated volatile anaesthetic, isoflurane, on the hypothalamo-hypophyseal-thyroid-suprarenal axis were studied. In fact, it was important to prove whether this new halogenated anaesthetic would provide better protection, for the patient, from surgery and anaesthetic stress compared with other anaesthetic agents in use. The study was carried out in 16 young class ASA I patients who were to undergo appendicectomy. Before and during operation, blood was taken to measure ACTH, cortisol, TSH, T3, T4 and PRL plasma levels. A remarkable increase of PRL, cortisol and T4 plasmatic rate was found, especially at the end of the operation. It was concluded that isoflurane, just like enflurane, did not prevent the increase of PRL, cortisol and T4 that usually takes place during surgery.

Influence of cerebral spinal fluid on the affinity of human red cells for oxygen

The oxygen affinity of washed red cells suspended in their own plasma or in CSF has been studied to demonstrate a possible effect of CSF on the oxygen affinity of human haemoglobin. The CSF was found to reduce the oxygen affinity of haemoglobin significatively, and this was not imputable to the action of pH, PCO2, temperature, 2,3DPG A hypothesis to explain the data found and their clinical interest towards the regulation of brain oxygenation was formulated considering the Monod-Wyman-Changeux model and the effect of solutions on proteins.

A visual representation of a model for monitoring the state of oxygenation in the critically ill patients. Description and clinical validation

The authors propose a new circular diagram for monitoring the oxygenation status of critically ill patients. This diagram contains some well known parameters; other ones are suggested to evaluate the pulmonary function and the capability of blood oxygenation. The calculation and a "BASIC" program are provided to use the diagram. This method offers a fast and easy monitoring of oxygenation status by a very small arterious and central venous blood sample.

[Effect promoting the rejection of an allograft of skin in rabbits treated with a high dose of amethopterin]

Present results show that the preventive inoculation of a single high dose of ametopterin (Methotrexate: MTX) may induce in rabbits the accelerated rejection of a skin allograft. This finding is sustained by an enhancing or adjuvant action of the agent on the mechanism of cell-mediated immunity.

Correction of the unfavourable effects of vasopressin by nitroglycerin infusion

Nitroglycerin was administered with vasopressin to prevent adverse effects. Vasopressin 0.25U . 70 kg-1 min-1 was infused intravenously in four dogs for 40 minutes, when a venous infusion of nitroglycerin 1.2 micrograms . kg-1 . min-1 was added for 20 minutes. Nitroglycerin 1.2 micrograms . kg-1 . min-1 alone was infused intravenously in another four dogs for 40 minutes. The venous blood pressures (mesenteric and central) and arterial pressures (mesenteric and femoral), the electrocardiogram and arterio-venous difference were recorded. Nitroglycerin was shown to annul the unfavourable effects of vasopressin without altering its efficacy upon portal pressure.

[Experimental research on hemorrhagic shock in the rabbit. Acid-base equilibrium and survival with 6-methylprednisolone and gelatin administration]

A previously described method was used to induce haemorrhagic shock in the rabbit by removing 40% of the circulating mass. This had been previously established as 2.6 +/- 0.5 kg-1 by a radioisotopic technique. Survivals were determined 1 and 2 weeks later after treatment with 40 mg/kg-1 6-MPD and vascular refilling with 3.5% gelatine equal to the amount removed. The blood gas analysis and EAB findings suggested that haemorrhagic shock includes both a fast and a slow physiopathological stage, and that the results of treatment are strictly linked to the time of its commencement. Metabolic acidaemia and respiratory alkalosis was constant, and all the controls died within 2 days, 6-MPD was not able to normalise the EAB, but ensured 100% survival at 2 weeks. Gelatin brought the lab data close to normal, but only ensured 100% survival at 2 weeks if given immediately after the removal of blood.

[Blood level of thyroid hormones in surgical thyroid diseases. Pre-,intra- and post-operative T3 and T4 levels]

A pre-, intra- and post-operative determination of thyroid hormone in values in the peripheral and thyroid vein reflux blood of patients with thyroid disorders requiring surgery showed that the so-called intraoperative squeezing of the gland either does not place or is of little importance when delicate surgical movements are commenced. A low incidence of intraoperative arrhythmia was also noted. Prevention of the latter is not indicated, since it is often dependent on surgical movements and/or unorthodox anaesthesiological management.