Starch–poly(ethylene-co-acrylic acid) composite films. Effect of processing conditions on morphology and properties

Formulations containing 4 parts cornstrach, 5 parts poly(ethylene-co-acrylic) (EAA), 1 part urea, and 1.6 parts of either water or aqueous ammonia were extruded at either 110–120°C or 150–160°C; and the resulting extrudates were then extrusion-blown into films. Complex formation between EAA and starch was measured by either X-ray diffraction or by solvent extraction of uncomplexed EAA. Although the processing temperature had only a minor effect on the amount of EAA complexed by starch, use of aqueous ammonia rather than water in these formulations increased the amount of complexed EAA by about a factor of 2. In films prepared with aqueous ammonia, the polysaccharide phase was present as submicron-sized domains. When ammonia was omitted from these formulations, the polysaccharide phase was less uniform in size and contained particles that were over an order of magnitude larger than those observed with ammonia.     

Effect of intrathecal morphine on blood glucose, glucagon and tissue glycogen in rat: comparison with the effect of xanthan gum on blood glucose

Eleven patients suffering from chronic disabling tinnitus underwent an FDG-PET study (positron emission tomography with [18F]deoxyglucose). Nine tinnitus patients revealed a significantly increased metabolic activity in the left, 1 in the right primary auditory cortex (PAC, Brodmann area 41). These results were statistically significant when compared to 14 healthy control individuals without tinnitus. A negative result was obtained from a chronic tinnitus patient but who had no subjective complaints during the period of PET investigation. One patient was first investigated during a disabling tinnitus period, later during a period with tinnitus relief and again when suffering from severe tinnitus. The metabolic activity of his left PAC was in good accordance with the subjective degree of tinnitus complaints present during each PET investigation. Although for the first time these results give objective evidence of tinnitus sensation and localization, they are difficult to interpret because of the limited research data available that combine functional brain imaging and acoustic stimuli.     

Effects of aging and schedules of knowledge of results on motor learning

Little research has been conducted on aging and the learning of motor skills. In this study, we examined the effects of different schedules of knowledge of results (KR) on the acquisition and retention of a movement timing task by young adults (20-23 years) and older adults (60-82 years). The results indicated that there were differences between young and older adults in the accuracy and consistency of motor performance when KR was provided. Accuracy effects persisted during a retention interval when KR was no longer provided, although there were no differences in variability. There were no interactions of age with any of the KR-related variables. These findings suggest that the ability to process KR, and the effects of KR on motor learning, are similar in young and older adults. These findings are discussed in terms of age-related issues in movement control and learning processes.     

Aldosterone and dexamethasone stimulate calcineurin activity through a transcription-independent mechanism involving steroid receptor-associated heat shock proteins

1. PD 81,723 has been shown to enhance binding of adenosine to A1 receptors by stabilizing G protein-receptor coupling ('allosteric enhancement'). Evidence has been provided that in the perfused hearts and isolated atria PD 81,723 causes a sensitization to adenosine via this mechanism. 2. We have studied the effect of PD 81,723 in guinea-pig isolated atrial myocytes by use of whole-cell measurement of the muscarinic K+ current (I[K(ACh)]) activated by different Gi-coupled receptors (A1, M2, sphingolipid). PD 81,273 caused inhibition of I[K(ACh)] (IC50 approximately 5 microM) activated by either of the three receptors. Receptor-independent I[K(ACh)] in cells loaded with GTP-gamma-S and background I[K(ACh)], which contributes to the resting conductance of atrial myocytes, were equally sensitive to PD 81,723. At no combination of concentrations of adenosine and PD 81,723 could an enhancing effect be detected. 3. The compound was active from the outside only. Loading of the cells with PD 81,723 (50 microM) via the patch pipette did not affect either I[K(ACh)] or its sensitivity to adenosine. We suggest that PD 81,723 acts as an inhibitor of inward rectifying K+ channels; this is supported by the finding that ventricular I(K1), which shares a large degree of homology with the proteins (GIRK1/GIRK4) forming I[K(ACh)] but is not G protein-gated, was also blocked by this compound. 4. It is concluded that the functional effects of PD 81,723 described in the literature are not mediated by the A1 adenosine receptor-Gi-I[K(ACh)] pathway.     

Gastrointestinal autonomic nerve tumors. A clinicopathological, immunohistochemical, and ultrastructural study of 12 cases

The gastrointestinal autonomic nerve tumor (GAN tumor) is an uncommon stromal tumor of the intestinal tract and retroperitoneum first described by Herrera and associates in 1984. Distinction of GAN tumors from other gastrointestinal stromal tumors is based on electron microscopic findings. Thus far there have been 12 reported cases. We present an additional 12 GAN tumors, identified by us during 4 years. There were seven male and five female patients and they ranged in age from 10 to 85 years (mean: 58 years). Sites of the tumors were stomach (three), jejunum (two), ileum (four), mesentery (one), and retroperitoneum (two). Eight of the tumors measured > 10 cm in greatest dimension. Usually well circumscribed, the neoplasms were tan to light pink, sometimes hemorrhagic, and soft. There was a variety of histologic patterns including fascicles, palisades, and whorls. Mitotic activity varied from 0 to 23 mitosis per 10 high-power fields (HPF). Using a panel of 10 immunohistochemical stains, only vimentin was consistently positive. There was neuron-specific enolase reactivity in six and S-100 protein reactivity in two cases. All muscle markers were negative. Ultrastructural studies showed neuron-like cells with long axonic cytoplasmic processes ending in bulbous synapse-like structures containing dense-core neurosecretory granules and clear vesicles. Basement membrane was absent. These features are reminiscent of ganglia of the intestinal autonomic nervous system. The patients were followed for 5-125 months (mean of 26 months). Tumor recurred or metastasized to the liver in seven patients (58%) and four patients died with tumor. There were correlations between tumor size (> 10 cm), mitotic count (at least five per 10 HPF), and aggressive behavior.     

The effect of unilateral destruction of the head of the caudate nucleus with kainic acid on the structure of the wakefulness-sleep cycle and the EEG in rats

The wakefulness-sleep cycle characteristics changes in Wistar line rats after unilateral lesions of the neuronal elements of the caudate nucleus head with kainic acid (at sparing the conducting ways going through this structure) were studied. It was shown that in 4 days after acid injection the share of the active wakefulness and light slow-wave sleep is significantly increased, whereas the percentage of the passive wakefulness, deep slow-wave stage, and paradoxal sleep (up to 80%) is reduced. The wakefulness-sleep cycle in rats is completely normalized on the 7th day after injection. The obtained data allow to consider the caudate nucleus as a modulator for wakefulness-sleep cycle, that is the structure involved in the motive activity regulation.