Preparation of multivesicular liposomes

A novel type of liposome, named here multivesicular liposomes, was prepared by evaporation of organic solvents from chloroform-ether spherules suspended in water. Within each spherule were numerous water droplets that contained solutes to be trapped in liposomes upon solvent evaporation. Liposome preparations of different average diameters were made, varying from $\text{29 ± 10 μ}\text{m}$ to $\text{5.6 ± 1.7 μ}\text{m}$. The liposomes were morphologically characterized by light microscopy and transmission electron microscopy. Materials successfully trapped within the liposomes ranged in molecular size from glucose to nucleic acids. Extremely high percentages of encapsulation (up to 89%) were achieved.     

Does resistive loading decrease diaphragmatic contractility before task failure?

While sustaining a load that leads to taskfailure, it is unclear whether diaphragmatic fatigue developsprogressively or occurs only at task failure. We hypothesized thatincremental loading produces a progressive decrease in diaphragmaticcontractility ever before task failure. Ten subjectsgenerated 60% of maximal transdiaphragmatic pressure(Pdi_max) for 2 min, 4 min, anduntil task failure. Before loading, 20 min after each period ofloading, and ~20 h after the last period of loading,Pdi_max, nonpotentiated andpotentiated Pdi twitch pressure(Pdi_tw), and the pattern of respiratory muscle recruitment during aCO₂ challenge were recorded. Sensation of inspiratory effort at the 4th min of the task-failure protocol was greater than at the same time in the preceding 4-min protocol. Surprisingly, potentiatedPdi_tw andPdi_max were reduced after 2 min ofloading and decreased further after 4 min of loading and after taskfailure; nonpotentiated Pdi_tw wasreduced after 4 min of loading and after task failure. The gastricpressure contribution to tidal breathing during aCO₂ challenge decreased progressively in relation to duration of the preceding loading period,whereas expiratory muscle recruitment progressively increased. A restperiod of ~20 h after task failure was not sufficient to normalizethese alterations in respiratory muscle recruitment or fatigue-inducedchanges in diaphragmatic contractility. In conclusion, while sustaininga mechanical load, the diaphragm progressively fatigued, ever beforetask failure, and when challenged the rib cage-to-diaphragmaticcontribution to tidal breathing and recruitment of the expiratorymuscles increased pari passu with duration of the preceding loading.

     

Isolation and partial characterization of an opioid-like 88 kDa hibernation-related protein

Previous studies show that infusion of hibernating woodchuck albumin (HWA) induces hibernation in summer-active ground squirrels and results in profound behavioral and physiological depression in primates. These effects are reversed by the administration of opiate antagonists, suggesting that the putative hibernation induction trigger (HIT) may act through opioid receptors. We have demonstrated that both HIT-containing plasma and the synthetic α opioid -Ala²- -Leu⁵-enkephalin (DADLE), which mimics the activity of HIT in hibernators, extend tissue survival time of a multi-organ autoperfusion system by 3-fold. In this study we present the first data showing biological activity with a much more highly purified plasma fraction from hibernating woodchucks, identified as the hibernation-related factor (HRF). Both the HRF and DADLE show opiate-like contractile inhibition in the mouse vas deferens (Mvd) bioassay. We also have preliminary evidence in an isolated rabbit heart preparation indicating that the HRF and DADLE act similarly to restore left ventricular function following global myocardial ischemia. Furthermore, we have partially sequenced an α 1-glycoprotein-like 88 kDa hibernation-related protein (p88 HRP) present in this fraction, which may prove to be the blood-borne HIT molecule.     

Differential enumeration of silage inoculants based on utilization of enzymatic activity and antibiotic sensitivity of bacteria

The differences in the composition of culture media inoculated with strains of Leuconostoc oenos were more quantitative than qualitative. Both temperature of incubation and pH significantly affected bacterial growth, the rates of substrate consumption and consequently the amount of metabolites produced. All strains degraded 5 g 1^-1 malate, except one at pH 3.5 and 25°C. Malate was metabolized before glucose except at higher pH (4.0 and 4.5) and temperature (32°C). Citrate was completely metabolized and its consumption rate was pH- and temperature-dependent. Neither acids contributed energy for growth as the Y_glu remained constant in the presence or absence of acids. There was a significant increase in fructose consumed at higher temperature. Also, the final concentration of mannitol was higher but not significantly different. The addition of acids, particularly citrate, significantly repressed mannitol formation.     

Radiation shielding parameters of some antioxidants using Monte Carlo method

In this paper, radiation shielding parameters such as mass attenuation coefficients and half value layer (HVL) of some antioxidants are investigated using MCNPX (version 2.4.0). The validation of the generated MCNPX simulation geometry for antioxidant structures is provided by comparing the results with standard WinXcom data for radiation mass attenuation coefficients of antioxidants. Very good agreement between W?NXCOM and MCNPX was obtained. The results from the validated geometry were used to calculate the shielding parameters of different antioxidants. The radiation attenuation properties of each antioxidant were compared with each other. The results showed that, on average, the highest and the lowest radiation mass attenuation coefficients were observed on hesperidin and delphinidin chloride, respectively. It can be concluded that Monte Carlo simulation is a strong tool and an alternate method where experimental investigations are not possible and a standard simulation setup can be used in further studies for different biological structures. It can also be concluded that the obtained results from this study are very useful for radiology and radiotherapy applications where antioxidants are frequently used.