Synchrony and social connection in immersive Virtual Reality.

Synchronising movements in time with others can have significant positive effects on affiliative attitudes and behaviors. To explore the generalizability of synchrony effects, and to eliminate confounds of suggestion, competence and shared intention typical of standard laboratory and field experiments, we used an Immersive Virtual Reality (VR) environment. Participants, represented as virtual humans, took part in a joint movement activity with two other programmed virtual humans. The timings of the co-participant characters' movements were covertly manipulated to achieve synchrony or non-synchrony with the focal participant. Participants in the synchrony condition reported significantly greater social closeness to their virtual co-participants than those in the non-synchrony condition. Results indicate that synchrony in joint action causes positive social effects and that these effects are robust in a VR setting. The research can potentially inform the development of VR interventions for social and psychological wellbeing.

Stability and sterility of biosynthetic human insulin stored in plastic insulin syringes for 28 days.

The stability and sterility of biosynthetic human insulin products stored at refrigerator and room temperatures in two types of plastic syringes and the stability of preservatives in the products were studied. Four types of biosynthetic human insulin were used: regular, isophane, combination, and extemporaneously prepared combination. Samples (0.4 mL) were withdrawn from multiple-dose vials into 39 polypropylene and 39 propylene-ethylene copolymer syringes. Three syringes of each type were analyzed immediately; the remaining syringes were stored in plastic bags, half at room temperature (23 degrees C) and half in the refrigerator (4 degrees C). A vial of each type of insulin was maintained under similar conditions. At days 1, 3, 7, 14, 21, and 28, samples from each syringe were analyzed by high-performance liquid chromatography for insulin potency and m-cresol and phenol concentrations. Samples of each product were also tested for sterility after 1, 2, and 4 weeks of storage at 4 degrees C and 23 degrees C. The potency of insulin in each of the biosynthetic human insulin products did not change significantly during the 28-day study in both types of plastic syringes and at both temperature settings. m-Cresol concentrations decreased in all samples; greater decreases occurred in samples stored at room temperature and in samples stored in polypropylene syringes. Phenol concentrations were less affected than m-cresol concentrations; greater decreases occurred in samples stored at room temperature. No significant decreases in insulin potency or m-cresol or phenol concentrations occurred in control samples stored in vials kept under similar conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced intestinal absorption of cyclosporine in rats through the reduction of emulsion droplet size.

The intestinal absorption of cyclosporine was measured in situ in rats using an olive oil emulsion prepared by either stirring or homogenization. The surface area of the homogenized dosage form was twice that of the stirred dosage form. The apparent permeability of cyclosporine from the homogenized emulsion was about twice that of the emulsion prepared by stirring. The examination of absorption in different intestinal segment lengths suggested the presence of an "absorption window." The absorption of cyclosporine appeared to be concentration independent and, therefore, non-carrier mediated. The dependence of absorption upon the intestinal perfusion rate suggested that the stagnant aqueous layer is the rate-limiting barrier in cyclosporine absorption. These results indicate that the bioavailability of cyclosporine administered in an emulsion can possibly be increased by enhancing its rate of absorption through the reduction of droplet size.

Temperature dependence of di-2-ethylhexyl phthalate (DEHP) pharmacokinetics in rainbow trout.

Rainbow trout (Salmo gairdneri) acclimated at 6, 12, or 18 degrees C received 400 micrograms [14C]DEHP/kg as an intraaortic bolus. DEHP disappeared rapidly from plasma, with an estimated 50% of the dose eliminated after 5 hr. Plasma concentration-time data were analyzed using a three-compartment model and by the statistical moment method; both analyses yielded similar parameter estimates. The apparent steady-state volume of distribution (Vss) and the apparent volume of the deep peripheral compartment (V3) increased exponentially with increasing temperature (log V proportional to temperature) while the volumes of the central (V1) and shallow peripheral (V2) compartments were not systematically affected. The total body clearance of DEHP increased linearly with increasing temperature, while the capacity to hold DEHP increased more rapidly, resulting in the biological persistence and potential for bioaccumulation of DEHP to increase with increased temperature. Both the terminal elimination half-life and the mean residence time increased exponentially with increasing temperature; the half-life increased from 79.5 to 130 hr between 6 and 18 degrees C. Simulations with the model indicated that the distribution of DEHP was temperature sensitive; this finding may have important implications for the temperature sensitivity of DEHP toxicity or carcinogenicity.

A new parenteral emulsion for the administration of taxol.

Taxol (NSC-125973) is a poorly soluble plant product that exhibits excellent antimitotic properties. This study involves the development of a new formulation for taxol. The stability of taxol in a 50% triacetin emulsion as well as possible methods of intravenous administration of this dosage form was examined. A stable emulsion was found at taxol concentrations of 10 and 15 mg/ml of emulsion. The 50% triacetin emulsion showed an intravenous LD50 of 1.2 ml/kg in Swiss-Webster mice. The 10 mg/ml taxol formulation was demonstrated to be stable upon addition to 5% dextrose iv fluids provided that small packing systems were used. The taxol-triacetin emulsion can also be intravenously injected at various rates, and it may prove to be a useful formulation for taxol.

X-ray powder diffraction and microscopic analysis of crystalluria in dogs with ethylene glycol poisoning.

Most of the urinary crystals in 2 dogs intoxicated with ethylene glycol had prismatic (rod-like, hippurate-like), and to a less extent, hemp seed or spindle shapes. Using X-ray powder diffraction and optical analysis, these crystals were identified as calcium oxalate monohydrate. A few crystals of calcium oxalate dihydrate (envelope shape) were also observed in the urine sediment. Their presence was confirmed by the appearance of weak X-ray peaks having interplanar spacings ranging from 0.617 to 0.620 nm, which are thought to correspond to the 200 X-ray reflection of calcium oxalate dihydrate. Thus, the 6-sided hippurate-like crystals in the urine of ethylene glycol-poisoned dogs are actually calcium oxalate monohydrate.

Low-dose ethanol in the treatment of ethylene glycol poisoning.

A pharmacokinetic study was conducted to determine the effectiveness of lower doses of ethanol in the treatment of ethylene glycol (EG) poisoning. Four dogs were maintained at serum ethanol concentrations of 0, 35 and 140 mg/dl prior to EG (i.v., 2 ml/kg) administration. The serum EG concentration-time data showed that the 35 mg/dl ethanol level provided as effective an inhibition of EG metabolism as did the 140 mg/dl level. The average urinary excretion rate of oxalic acid post EG administration was reduced to control levels by ethanol. The 35 mg/dl serum ethanol level reduced the total body clearance of EG from 93.9 to 50.0 ml/h/kg and increased the effective half-life from 5.78 to 11.4 h. Clinical testing was accomplished by giving the dogs 12 ml EG/kg body weight orally. One hour later, the dogs were either not treated or treated with a sodium bicarbonate-ethanol solution to obtain a serum ethanol concentration of 50 mg/dl. The clinical test performed in the ethanol-treated dogs showed little change from normal limits. Urine calcium oxalate crystals were seldom found. The dogs given EG (12 ml/kg) but not treated with ethanol were in a coma at 13 h and showed severe metabolic acidosis, dehydration, mild hepatocellular disease and acute renal damage. Urine calcium oxalate crystals were found in high numbers. The rapid death associated with EG poisoning appeared to be due to metabolic acidosis in combination with dehydration.