Acquisition of vimentin in astrocytes cultured from postnatal rat brain

Summary Vimentin and glial fibrillary acidic protein (GFAP) represent the principal constituents of intermediate filaments found in astrocytes. In contrast to vimentin—GFAP transition which occurs during glial developmentin situ, vimentin coexists with GFAP in cortical astrocytes allowed to differentiate in culture. To examine whether culture conditions or proliferative activity of the cells is responsible for the expression of vimentin, we generated cultures of GFAP-positive, vimentin-negative astrocytes isolated from 26-day postnatal rat brain cortices. Isolated astrocytes are characterized by a very thin rim of perinuclear cytoplasm and by numerous processes. Antiserum to GFAP labelled major processes and cell somata of some astrocytes, especially those with relatively short and large processes. Within 3 days in culture, all astrocytes accumulated GFAP in hypertrophic cell bodies and many began to express vimentin. Vimentin appeared primarily close to nuclei, and filaments of vimentin extended into proximal segments of the cell processes. In some astrocytes, however, vimentin was always absent. Combined double immunolabelling and histoautoradiography experiments demonstrated that the acquisition of vimentin was independent of the ability of astrocytes to incorporate tritiated thymidine. The results indicate that astrocytes isolated from 26-day postnatal rat brain are heterogeneous with respect to their ability to express vimentin and that vimentin synthesis is not correlated with the growth state of the cells as had been previously suspected.     

Our experience with diagnostics of congenital disorders of glycosylation

The aim of this study is to report our 3years experience with the screening of congenital disorders of glycosylation. A common isoelectric focusing method with immunofixation was used for analysis of serum transferrin and alpha1-antitrypsin, apart from several other procedures. A group of about 1000 individuals, both healthy controls and patients, mostly with signs of a metabolic disease were examined. Here we present an overview of (1) hypoglycosylation findings, (2) distribution of protein variants, (3) misguiding rare Tf variants found in our set, and (4) association of some phenotypes with various diseases.     

Polymerization of lactams, 55. Cyclic dimer of 6-caprolactam and its polymerization

Polymerization of the cyclic dimer of 6-caprolactam was investigated in N-methyl-2-pyrroli-done solution at 260°C under initiation with 6-aminocaproic acid or anhydrous phosphoric acid on the one hand, and in the solid phase at 230, 260, and 280°C in the absence of any other component or under initiation with anhydrous phosphoric acid, on the other. Monomeric 6-caprolactam was formed in all cases already at the beginning of reaction. It has been suggested that, in addition to the direct incorporation of the cyclic dimer into a polymer chain, the dimer is alos incorporated via the monomer, which is formed from the dimer by an intermolecular transamidation reaction.     

Structure and stability of poly(vinyl chloride), 4. Unsaturated ketones and their role in the initiation of thermal degradation

The thermal dehydrochlorination of poly(vinyl chloride) (PVC) in an inert atmosphere was investigated by the continuous potentiometric method. The effect of the structure of alicyclic and aliphatic α,β-unsaturated ketones on the rate of dehydrochlorination was examined, and a new mechanism of initiation for the dehydrochlorination of PVC was suggested. The results obtained demonstrate that the basic cause of the thermal instability of PVC are structures of the type of cisoid α,β-unsaturated ketone, dienone, or polyenone which by the dehydrochlorination of regular structural PVC units form isolated double bonds which, in turn, initiate the chain dehydrochlorination of PVC by allyl activation.     

Comparative study of complications after primary and revision transsphenoidal endoscopic surgeries

Neurosurgical Review - A preferred treatment for residual/recurrent pituitary adenomas has not been established. The existence of higher complication rates for revision surgeries remains under...     

Mutagenic activity in waste from an aluminum products factory in Salmonella/microsome assay

The mutagenic activity of waste material originating from an aluminum products factory was determined by the Salmonella/microsome assay, using the bacterial strains TA100, TA98 and YG1024. The material was obtained by sweeping the factory floor at the end of the work shift. Organic compounds were extracted by ultrasound for 30 min in dichloromethane or 70% ethanol. After evaporation of solvent, these extracts were dissolved in dimethylsulfoxide, and tested for the mutagenic activity at varying concentrations. All the extracts from the factory had mutagenic activity, especially in the YG1024 strain, suggesting the presence of aromatic amines, later confirmed by chemical analysis. The TA98 strain also showed mutagenic activity, though it did not exhibit the highest mutagenicity index observed with the YG1024 strain. In TA100, mutagenic activity was not observed. This study should serve as an alert to management and those who are occupationally exposed, and as a warning that this type of waste should not be discarded in the environment without any control.     

The ankle-brachial blood pressure index as a risk indicator of generalized atherosclerosis

Contemporary methods of assessment of possible cardiovascular disease based on traditional risk factors are not perfect. Therefore new ways are sought. Simple and inexpensive methods include assessment of the blood pressure on the lower extremities above the ankles. The finding of a reduced ratio of the ankle-brachial blood pressure index (ABI) indicates atherosclerosis of the lower extremity arteries. ABI values of 0.9 or less are associated with a significantly increased risk of cardiovascular diseases (in particular myocardial infarction and stroke) that is independent of other risk factors. ABI assessment is a simple clinical examination and should be performed in middle-aged and elderly subjects with a medium and high cardiovascular risk in order to define more accurately their health status. Patients with reduced ABI of 0.9 or less are candidates for secondary preventive treatment for cardiovascular disease.     

Addition of zinc methacrylate in dental polymers: MMP-2 inhibition and ultimate tensile strength evaluation

This study evaluated the effect of zinc methacrylate (ZM) on the inhibition of matrix metalloproteinase 2 (MMP-2) and the ultimate tensile strength (UTS) of an experimental polymer. Enzymes secreted from mouse gingival tissues were analyzed by gelatin zymography in buffers containing 5 mM CaCl₂ (Tris–CaCl₂) in 50 mM Tris–HCl buffer with various concentrations of ZM (0.5, 1, 2, 4, 8, and 16 mM). The matrix metalloproteinases present in the conditioned media were characterized by immunoprecipitation. The polymer UTS evaluation was performed in eight groups with various concentrations of ZM (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt.%), in a mechanical testing machine. MMP-2 (62 kDa) was detected in the zymographic assays and inhibited by ZM in all tested concentrations. UTS data were submitted to one-way ANOVA and Tukey's test (α = 0.05), and no significant differences were observed among groups, except in the polymer containing 30% ZM, presenting a significantly lower value when compared with the control group (p < 0.05). The results suggest that ZM inhibits MMP-2 expression in all concentrations tested, while small concentrations did not affect the ultimate tensile strength of the polymer. Zinc methacrylate is a metalloproteinase inhibitor that can be copolymerized with other methacrylate monomers. Yet, the addition of ZM did not affect the resin bond strength. Thus, in vivo tests should be performed to evaluate the performance of this material.