Phase-field Determination of NaSICON Materials in the Quaternary System Na2 O-P2 O5 -SiO2 -ZrO2 : The Series Na3 Zr3-x Si2 Px O11.5+x/2.

Two types of solid electrolytes have reached technological relevance in the field of sodium batteries: ß/ß"-aluminas and NaSICON-type materials. Today, significant attention is paid to room-temperature stationary electricity storage technologies and all-solid-state Na batteries used in combination with these solid electrolytes are an emerging research field besides sodium-ion batteries. In comparison, NaSICON materials can be processed at lower sintering temperatures than the ß/ß"-aluminas and have a similarly attractive ionic conductivity. Since Na2 O-SiO2 -ZrO2 -P2 O5 ceramics offer wider compositional variability, the series Na3 Zr3-x Si2 Px O11.5+x/2 with seven compositions (0≤x≤3) was selected from the quasi-quaternary phase diagram in order to identify the predominant stability region of NaSICON within this series and to explore the full potential of such materials, including the original NaSICON composition of Na3 Zr2 Si2 POl2 as a reference. Several characterization techniques were used for the purpose of better understanding the relationships between processing and properties of the ceramics. X-ray diffraction analysis revealed that the phase region of NaSICON materials is larger than expected. Moreover, new ceramic NaSICON materials were discovered in the system crystallizing with a monoclinic NaSICON structure (space group C2/c). Impedance spectroscopy was utilized to investigate the ionic conductivity, giving clear evidence for a dependence on crystal symmetry. The monoclinic NaSICON structure showed the highest ionic conductivity with an optimum ionic conductivity of 1.22×10-3 at 25 °C for the composition Na3 Zr2 Si2 PO12 . As the degree of P5+ content increases, the total ionic conductivity is initially enhanced until x=1 and then decreases again. Simultaneously, the increasing amount of phosphorus leads a decrease in the sintering temperatures for all samples, which was confirmed by dilatometry measurements. The thermal and microstructural properties of the prepared samples are also evaluated and discussed.

4-Aminopyridine kinetics.

Nine healthy subjects (7 men; 2 women) received single 20-mg IV injections of 4-aminopyridine (4-AP). Six of the subjects received the same dose in the form of enteric-coated tablets and four the same dose in uncoated tablets; treatments were at least 2 wk apart. Blood, saliva, and urine were assayed for 4-AP using a high-performance liquid chromatography. Kinetic analysis of serum concentrations after intravenous dosing resulted in the best fitting of a triexponential model in five and a biexponential model in four subjects. The apparent volume of distribution (V) was 2.6 +/- 0.9 (mean +/- SD) 1 kg-1, the terminal half-life (t 1/2) 3.6 +/- 0.9 hr, and the total serum clearance 0.61 +/- 0.14 1 hr-1 kg-1. Saliva concentrations were higher than those in serum after 5 min, with a mean correlation coefficient of 0.989 (n = 5). The t 1/2 and V calculated from serum and saliva concentrations were of the same order. The total urinary excretion of unchanged 4-AP was 90.6 +/- 7.8% after intravenous doses and 88.5 +/- 4.8% after oral doses of enteric-coated tablets. The bioavailability of the enteric-coated tablets calculated from the area under the serum concentration curve (95 +/- 29%) did not differ from that calculated from urinary excretion (98 +/- 8%). Protein binding of 4-AP was found to be negligible. Biotransformation is unlikely.

A disposable in vivo oxygen electrode for the continuous measurement of arterial oxygen tension.

An evaluation of the accuracy, perdision, and clinical safety of the IBC indwellling catheter electrode for the continuous monitoring of arterial oxygen tension during and after general anesthesia was made in a total of 62 patients. A comparison of the standard bench-type electrode (Radiometer) with the International Biophysics Corporation (IBC) electrode for the measurement of oxygen tension in tonometered blood also was performed. Three hundred and fifty comparisons in 51 patients were made of the indwelling electrode with a standard Radiometer unit and, while there was good correlation, there also was ome scatter. An additional small series of 44 comparisons in 11 patients was performed, the primary difference being that the electrode was maintained intr-arterially for approximately 1 day. In both in vivo studies there was excellent correlation but questionable precidion. Four IBC electrodes and eight Radiometer Pao2 electrodes in an additional study were compared at 11 different tonometered oxygen tensions in blood. The IBC electrodes measured oxyygen tension more accurately than did the Radiometer, and standard deviations were consistently smaller at all of 11 different oxygen tensions for the IBC unit. The authors believe that the poor precision within both in vivo studies might be due to the fact that the IBC probe, which was of unknown accuracy and precision, was compared to a standard device (the Radiometer) which in the in vitro investigation proved to be less accurate and less precise. No complications due to the insertion and maintance of this in vivo electrode were encountered. The authors suggest that the IBC method for measuring Pao2 continuously in vivo be considered as an alternative to intermittent gas analysis of oxygen tension.

Purification and characterization of a poly-L-lysine-activated serine endoprotease from Lumbricus rubellus.

An endoprotease in earthworm (Lumbricus rubellus) is purified to apparent homogeneity using 125I-lactalbumin as a substrate. The protease has a molecular mass of 27 kDa and is markedly activated by poly-L-lysine or poly-L-arginine. It is a chymotrypsin-like serine protease. Its activity is distributed to coelomic fluid but relatively little to coelomocytes.

The treatment of recurrent arthrogrypotic club foot in children by the Ilizarov method. A preliminary report.

Between 1994 and 1997 we used the Ilizarov apparatus to treat 12 recurrent arthrogrypotic club feet in nine patients with a mean age of 5.3 years (3.2 to 7). After a mean of three weeks (two to seven) for correction of the deformity and 1.5 weeks (one to four) for stabilisation in the apparatus, immobilisation in a cast was carried out for a mean of 14 weeks (7 to 24). The mean follow-up period was 35 months (27 to 57). Before operation there were one grade-II (moderate), eight grade-III (severe) and three grade-IV (very severe) club feet, according to the rating system of Dimeglio et al. After operation, all the club feet except one were grade I (benign) with a painless, plantigrade platform. Radiological assessment and functional evaluation confirmed significant improvement. Two complications occurred in one patient, namely, epiphysiolysis of the distal tibia and recurrence of the foot deformity. These results suggest that our proposed modification of the Ilizarov technique is effective in the management of recurrent arthrogrypotic club foot in young children.

Usefulness of 99Tcm-MDP knee SPET for pre-arthroscopic evaluation of patients with internal derangements of the knee.

The aim of this study was to ascertain whether knee SPET can localize lesion sites in patients with internal derangements of the knee. We performed knee SPET as a pre-arthroscopic examination in 63 consecutive patients. SPET imaging was performed with a triple-headed SPET camera 4 h after the injection of 99Tcm-methylene diphosphonate. Arthroscopic diagnoses were as follows: 28 medial meniscus injuries, 24 lateral meniscus injuries, 31 anterior cruciate ligament (ACL) injuries, three posterior cruciate ligament injuries and one medial collateral ligament injury. Of 30 patients with crescent-shaped increased activity at the medial tibial plateau, 22 had medial meniscus injuries (positive predictive value: PPV 73%); of 17 patients with crescent-shaped activity at the lateral tibial plateau, 13 had lateral meniscus injuries (PPV 76%). Of 18 patients with increased activity at ACL attachment sites (primary sign), 17 had ACL injuries (PPV 94%). Of 27 patients with increased activity at bone impaction sites of ACL injury (secondary sign), 22 had ACL injuries (PPV 81%). Of 32 patients who had either a primary or secondary sign, 26 had ACL injuries (PPV 81%). We conclude that knee SPET is very useful in the management of internal derangements of the knee, particularly in determining the need for arthroscopy by localizing lesion sites.

Cardiovascular and neuromuscular effects of Org NC 45, pancuronium, metocurine, and d-tubocurarine in dogs.

We compared the cardiovascular and neuromuscular effects of Org NC 45 with those of pancuronium, metocurine, and d-tubocurarine in six dogs anesthetized with halothane. The ED90 (dose of drug which produced a 90% depression of twitch tension) of Org NC 45, pancuronium, metocurine, and d-tubocurarine was 14 +/- 3, 22 +/- 3, 63 +/- 19, and 130 +/- 19 micrograms/kg, respectively. All subsequent neuromuscular and cardiovascular effects were determined from a dose equal to 3 times the ED90 of muscle relaxant. Org NC 45, pancuronium, metocurine, and d-tubocurarine produced a neuromuscular blockade with a during (time from relaxant administration until recovery 50% of the original twitch tension) of 42 +/- 2, 108 +/- 10, 109 +/- 21, and 100 +/- 19 minutes, respectively. Org NC 45 caused no significant cardiovascular changes. Pancuronium increased heart rate, mean arterial blood pressure, cardiac output, and pulmonary wedge pressure, and it decreased systemic vascular resistance (p less than 0.05). Although metocurine also increased heart rate and cardiac output (p less than 0.05), mean arterial blood pressure and pulmonary wedge pressure did not change. d-Tubocurarine decreased all cardiovascular parameters except heart rate which increased significantly (p less than 0.05). We conclude that Org NC 45 produces a neuromuscular blockade of shorter duration with fewer cardiovascular changes than that of pancuronium, metocurine, or d-tubocurarine.

The pharmacokinetics of d-tubocurarine in man with and without renal failure.

Plasma and urine concentrations of d-tubocurarine (d-TC) were determined and twitch tension was monitored before and after the intravenous administration of d-TC, 0.5 mg/kg in patients anethetized with halothane and nitrous oxide with (N=5) and without (N=5) renal failure. Terminal half lives of d-TC of 231 and 330 minutes predicted from other studies for patients with and without renal function were consistent with plasma concentrations measured. In patients with normal renal function, 38% of unchanged d-TC was eliminated in urine in 25 hours as opposed to 13% in those patients with a newly transplanted kidney. However, we still conclude that a newly transplanted kidney can eliminate d-TC effectively since the kidney was inserted 3.5 hours after administration of d-TC. Absence of renal function significantly prolonged the duration of neuromuscular blockade but did not alter the plasma concentrations of d-TC required for neuromuscular blockade. Thus, prolonged neuromuscular blockade from d-TC in patients with renal failure is due to decreased elimination rate of the drug as a consequence of lack of renal function rather than increased sensitivity.

Comparative pharmacokinetics and dynamics of vecuronium and pancuronium in anesthetized patients.

Plasma concentrations and the degree of neuromuscular blockade after a 2-min infusion of 0.1 mg/kg of vecuronium bromide or pancuronium bromide (equipotent doses) were studied in 12 gynecologic patients. The plasma concentrations of both drugs declined in a triphasic manner. The difference between the intercepts and rate constants of the two drugs was not significant. Vecuronium was removed faster from the plasma than pancuronium; this was reflected in a significantly larger plasma clearance rate for vecuronium (4 ml X min-1 X kg-1 vs 1.1 ml X min-1 X kg-1 for pancuronium). The effective plasma concentrations at 50% recovery of the twitch height were 0.11 +/- 0.02 (vecuronium) and 0.2 +/- 0.03 microgram/ml (pancuronium). The disposition kinetics were adequately described by a three-compartment model. An effect compartment was added to the model to correlate the neuromuscular effects and plasma concentrations of both drugs. The ratio between concentrations of vecuronium and pancuronium in the effect compartment at 50% twitch height was 0.83. In spite of its greater potency, vecuronium has a shorter duration of action than pancuronium.

Operating room temperature prior to surgical draping: effect on patient temperature in recovery room.

Assessment was made of whether a cold-room environment prior to surgical draping affected patient temperature or the incidence of shivering in the recovery room in patients undergoing major vascular surgery when warming blankets and warmed fluids were used to maintain intraoperative temperature. Forty-two patients scheduled to undergo major vascular surgery were randomly assigned in equal numbers to a "cold or "warm" room. Temperatures in the "warm" rooms were 22.2 C or above (range 22.8-25.6 C) until draping, and in "cold" rooms, 18.9 C or below (ranged 13.9-17.8 C). Once surgical drapes were placed, the room temperature control was set at its minimum, 17 C. All intravenous fluids and blood were warmed to 37.5 C, and a heating blanket was maintained at 37.8 C before and during the operative procedure. Patient temperatures initially did not differ between groups. Despite significantly greater heat loss prior to draping in the cold-room group (0.63 +/- 0.14 C) than in the warm-room group (0.32 +/- 0.10 C) (p < 0.01), there were no differences in temperature in the recovery room, shivering, myocardial, renal CNS, pulmonary, or graft morbidity in the two groups. In major intra-abdominal vascular operations the use of warming blankets and the practice of warming all fluids for infusion allow a comfortable room temperature without detriment to patient care.

Clinical pharmacology of ORG NC45 (NorcuronTM): a new nondepolarizing muscle relaxant.

To determine the neuromuscular effects of a new muscle relaxant, ORG NC45 (Norcuron), a monoquaternary homologue of pancuronium, 84 ASA Class I or II patients were studied under halothane and nitrous oxide anesthesia. The ED50 (dose of muscle relaxant causing a 50% depression of twitch tension) of pancuronium and ORG NC45 was 0.022 mg/kg (r = 0.90) and 0.015 mg/kg (r =0.80), respectively, for a potency ratio of 1.5 (0.022/0.015). The duration of action (time from injection to 90% recovery of control twitch tension) was 27 +/- 5 min with ORG NC45, 0.02 mg/kg, and 65 +/- 16 min with pancuronium in an equivalent dose of 0.03 mg/kg. The increase in duration of neuromuscular blockade from repetitive doses was greater with pancuronium than with ORG NC45. Reversal of an ORG NC45 neuromuscular blockade was accomplished with doses of neostigmine slightly less than those required for pancuronium. Under thiopental-nitrous oxide anesthesia, endotracheal intubation was easily performed using ORG NC45, 0.07-0.14 mg/kg. The duration of action of ORG NC45, 0.07 mg/kg, was about one-third that of pancuronium (0.1 mg/kg). It was concluded that ORG NC45 is more potent and has a shorter duration of action with both initial and repetitive doses than does pancuronium. With these characteristics and the reported lack of cardiovascular effects, the authors believe further clinical trials are warranted.

Clinical pharmacology of vecuronium and atracurium.

Vecuronium and atracurium provide addition flexibility to the clinician using neuromuscular blocking drugs. The shorter duration of action, lack of significant cardiovascular effects, and the lack of dependence on the kidney for elimination provide clinical advantages over, or alternatives to, currently available nondepolarizing neuromuscular blocking drugs.

Hepatobiliary disposition of vecuronium bromide in man.

The plasma and bile concentrations, the biliary excretion and the neuromuscular blocking effect of vecuronium bromide were studied during surgery in 13 patients who had received 150 micrograms kg-1 i.v. The amount of vecuronium in liver biopsies taken after i.v injection was measured in a separate group of six patients. Vecuronium appeared early in the bile, in concentrations that were 30-50 times greater than those in the plasma. On the basis of the measured amount of vecuronium excreted in the bile, together with the accepted average daily bile flow, it was estimated that more than 40% of vecuronium was excreted in the bile in 24 h. Liver biopsies indicated that the liver may contain more than 50% of the i.v. dose 30 min after injection. The large distribution of vecuronium into the liver may account for the initial rapid decline in vecuronium plasma concentration and its relatively short duration of action. In this study, neuromuscular blockade was prolonged, possibly as a result of interference, by surgical manipulation, with the rapid hepatic uptake of vecuronium.

Effects of furosemide on the neuromuscular junction.

These studies investigated the direct effects of furosemide on neuromuscular transmission using the in vitro rat phrenic nerve diaphragm and the in vivo at soleus nerve muscle preparations. Furosemide (10(-6)-10(-4)m) reduced the concentration of d-tubocurarine required to achieve 50% twitch tension depression in the indirectly stimulated rat diaphragm. Intraarterial injection of furosemide had a biphasic effect on the cat neuromuscular junction. At low doses (0.1-10.0 micrograms/kg) the drug had a depressant effect, reduced the force of muscle contraction, prevented nerve and muscle responses to NaF and dibutryl cyclic AMP, and intensified the neuromuscular blockade produced by d-tubocurarine and succinylcholine. In contrast, in higher doses (1-4 mg/kg) furosemide produced stimulus-bound repetitive neural activity, initiated neural activity, increased the force of muscle contraction, enhanced nerve and muscle responses to NaF and dibutyrl cyclic AMP, and antagonized d-tubocurarine and succinylcholine blockades. Furosemide had no effect on denervated preparations. High doses of furosemide inhibit non-competitively both the high- and low-affinity forms of the enzyme cyclic AMP phosphodiesterase in both soluble and particulate fractions of cat sciatic nerve. Thus, furosemide has direct effects on neuromuscular transmission, but the direction of these effects is dose-dependent.

Disposition and urinary excretion of vecuronium bromide in anesthetized patients with normal renal function or renal failure.

The effect and plasma concentrations of vecuronium bromide were measured in normal patients after an intravenous dose of 50, 100, or 150 micrograms/kg and in patients with renal failure after 50 or 100 micrograms/kg. Urinary excretion of vecuronium was studied in normal patients after the 150 micrograms/kg dose. Pharmacokinetic parameters of patients with or without renal failure were similar. No metabolites of vecuronium were found in the plasma. Twenty percent of vecuronium was excreted unchanged in the urine; 5% as the 3-hydroxy derivative. No other metabolites of vecuronium were found in the urine. Increasing doses of vecuronium shortened the onset, but prolonged the duration of action and the recovery rate, to a similar extent in patients with or without renal failure. It was concluded that the disposition of vecuronium was best described by a three compartment model. Both the disposition and the effect of vecuronium are only marginally disturbed by renal failure.

Focal fibrocartilaginous dysplasia of long bones: report of eight additional cases and literature review.

We report eight additional cases of focal fibrocartilaginous dysplasia (FFCD) in the proximal tibia (five), distal ulna (one), and distal femur (two). Spontaneous, complete resolution of the lesion was observed in two tibiae and one ulna. Three tibial lesions with genu varum deformity were managed with osteotomy. Two femoral FFCDs caused persistent or progressive deformity: one genu valgum with patellar dislocation, and one genu varum. These patients underwent concomitant deformity correction and lengthening by the Ilizarov method. The final results were satisfactory in all patients except one, who underwent valgus tibial osteotomy and developed mild postoperative genu valgum. The analysis of a total of 46 cases in the literature and our experience suggests that (a) FFCD has a wide histopathologic spectrum, ranging from purely dense, fibrous tendon-like tissue to benign fibrocartilaginous tissue; (b) at least 45% of tibial FFCD demonstrates progressive, spontaneous resolution; (c) in contrast, femoral and humeral FFCDs appear to have a slim possibility of spontaneous regression of the deformity; and (d) corrective osteotomy is indicated when the deformity is increasing or persistent, or when the existing deformity is severe enough to jeopardize adjacent joint mechanics and alignment.

Does anesthetic technique make a difference? Augmentation of systolic blood pressure during carotid endarterectomy: effects of phenylephrine versus light anesthesia and of isoflurane versus halothane on the incidence of myocardial ischemia.

Whether anesthetic technique affected the incidence of myocardial ischemia in 60 patients undergoing carotid endarterectomy was investigated. The patients were randomly assigned to receive halothane or isoflurane (with nitrous oxide) either at a low concentration alone or at a higher concentration with phenylephrine added to support blood pressure. Blood pressure was maintained within 20% of each patient's average ward systolic pressure. Seven leads of electrocardiograms (ECG) and echocardiograms were analyzed for segmental wall motion. The echocardiograms were analyzed using standard formulae for end-systolic meridional wall stress (SWS) and rate-corrected velocity of fiber shortening (Vcfc). Because of the nature of these calculations, only echocardiograms with normal regional wall motion could be accurately analyzed. The patients had postoperative ECG and creatinine phosphokinase (CPK) isoenzyme determinations and regularly scheduled clinical examinations to detect perioperative myocardial infarction and neurologic deficits. Although blood pressures were similar, the patients who received a higher concentration of anesthetic plus phenylephrine had a higher wall stress, regardless of the choice of anesthetic agent. All four techniques allowed provision of the same stump pressures (the marker surgeons used for adequacy of collateral carotid flow). No difference could be found in wall stress or incidence of myocardial ischemia between isoflurane and halothane. The patients who received phenylephrine had a threefold greater incidence of myocardial ischemia than did the patients who had light anesthesia to maintain similar systolic blood pressures and stump pressures. The groups were demographically and hemodynamically similar; in particular, the heart rates were not different.(ABSTRACT TRUNCATED AT 250 WORDS)