Task performance of black and white children across levels of presentation variability

This study is an examination of the task performance patterns of Black and White, working and middle-class American children across a nonvaried and a varied presentation format condition: the relation of such patterns to activity levels in the home and to standardized achievement was also examined. Performance was better under the varied than the nonvaried format condition. This pattern held for all ethnic group/class combinations with the exception of Black middle-class children, for whom performance under the two conditions was virtually identical. Moreover, Black children, especially Black working-class children, reported greater home activity levels than did their White counterparts. Neither home activity level nor achievement was functionally related to patterns of performance.     

Parotid gland metastases of two uncommon neoplasms with low metastatic potential

Oligodendrogliomas are uncommon intracranial glial tumours in which extracranial spread is only rarely reported. Similarly, both intracranial and ocular medulloepitheliomas are also rare, with metastatic spread from the ocular neoplasm being less common than its intracranial counterpart. We report cases of an intracranial oligodendroglioma and an ocular medulloepithelioma both of which metastasised to the parotid gland. To our knowledge these are only the second oligodendroglioma and the third ocular medulloepithelioma to be reported as metastasising to this site.     

Immunocytochemical localization of chymase to cytoplasmic vesicles after rat peritoneal mast cell stimulation by compound 48/80

The subcellular events responsible for release of mediators by mast cells may help to clarify roles for mast cells in health and disease. In this study we show that the granule-associated protease chymase is also within cytoplasmic vesicles in appropriately stimulated rat peritoneal mast cells. Rat peritoneal mast cells were recovered before or 1-10 sec after exposure to the secretogogue compound 48/80 (10 micrograms/ml) and then were examined by radioimmunoassay to quantify histamine release or were processed, using routine methods for postembedding immunoelectron microscopy, to identify the subcellular localization of chymase. In comparison to unstimulated cells, compound 48/80 stimulated cells in two independent experiments showed an increase (15%, 28%) in the surface area of the cell and a decrease (12%, 6%) in the surface area of the total granule compartment before degranulation channel formation. These global cellular changes occurred in a background of transient but significant (p < 0.01) increases in the area and number of chymase-immunoreactive vesicles per microns2 cytoplasm. These changes were detectable at 5 or 7 sec after stimulation with compound 48/80 but returned to near prestimulation levels by 9 or 10 sec after addition of compound 48/80 (total cumulative histamine release was 28% by 8 sec and 47% by 14 sec). These observations suggest that vesicles participate in the early stages of regulated secretion of chymase from rat peritoneal mast cells.     

The results of complex social and ecologic study in the city of Ufa

The authors present results of social and ecologic study carried out in Ufa. The results describe the course of ecologically important processes and phenomena in correlation with the public subjective understanding. Public health is influenced by hygienic parameters of food and water quality as well as a complex of social, economic and psychologic factors. Weak correlation between those parameters and ambient air pollution necessitates more accurate approach to ecologic mapping of cities and to manipulation with data on lower atmosphere pollution with chemical hazards.     

Stain therapy and reduced incidence of stroke. Implications of cholesterol-lowering therapy for cerebrovascular disease

Three recent large clinical trials-the West of Scotland Coronary Prevention Study, the Scandinavian Simvastatin Survival Study, and the Cholesterol and Recurrent Events Trial-have all confirmed that cholesterol lowering with HMG-CoA reductase inhibitors is safe and effective therapy to prevent an initial or recurrent coronary event in patients at high risk for coronary heart disease. However, a number of questions related to the treatment of lipid disorders and risk reduction for coronary heart disease remain, including the cholesterol concentration at which treatment would best be initiated, the optimal cholesterol reduction or goal to be attained, and the mechanisms by which HMG-CoA reductase inhibitors reduce the risk for clinical events.     

Sedimentation rates measurements in former channels of the upper Rh?ne river using Chernobyl 137Cs and 134Cs as tracers

Fibroblasts derived from patients with late infantile neuronal ceroid lipofucsinosis (NCL) and from a mouse model of NCL are similar to cells in intact animals in that they accumulate subunit 9 of mitochondrial F1F0-ATP synthase (F-ATPase) (Tanner, A., Dice, J.F., Cell Biol. Int. 19 (1995) 71-75). We now report no differences in the synthetic rates of F-ATPase subunit 9 in such affected cells when compared to control cells. However, the degradation rates of F-ATPase subunit 9 are reduced in both the affected human and mouse cells. This reduced degradation applies only to subunit 9 and the homologous vacuolar ATPase subunit among five distinct, reproducible proteolipid bands analyzed. Approximately 15% of newly synthesized F-ATPase subunit 9 is rapidly degraded in control cells, but this rapidly degraded component is absent in both the human and mouse NCL fibroblasts. At confluence, when the accumulated F-ATPase subunit 9 transiently disappears from human NCL fibroblasts, there is an increased degradation of all proteolipids. The pathway of degradation that is enhanced at confluence is likely to correspond to lysosomal macroautophagy. We confirmed that lysosomes were able to degrade F-ATPase subunit 9 after endocytosis of radiolabeled mitochondria. Human NCL fibroblasts were less active than control cells in this lysosomal degradation of endocytosed F-ATPase subunit 9. However, this difference was not specific for F-ATPase subunit 9 since it also applied to total endocytosed mitochondrial protein. We conclude that degradation of F-ATPase subunit 9 can occur by multiple pathways and that a mitochondrial pathway of proteolysis is defective in the late infantile human and mouse forms of NCL.     

Demonstration of a word design strategy for DNA computing on surfaces

A strategy for DNA computing on surfaces using linked sets of 'DNA words' that are short oligonucleotides (16mers) is proposed. The 16mer words have the format 5'-FFFFvvvvvvvvFFFF-3' in which 4-8 bits of data are stored in 8 variable ('v') base locations, and the remaining fixed ('F') base locations are used as a word label. Using a template and map strategy, a set of 108 8mers each of which possesses at least a 4 base mismatch with the complements to all the other members of the set (4bm complements) are identified for use as a variable base sequence set. In addition, sets of 4 and 12 word labels of the form ABCD....DCBA that are respectively 8bm and 6bm complements with each other are identified. The 16mers are chosen to have a G/C content of 50% in order to make the thermodynamic stability of the perfectly matched hybridized DNA duplexes similar; a simple pairwise additive method is used to estimate the perfect match and mismatch hybridization thermodynamics. A series of preliminary experiments are presented that use small arrays of 16mers attached to chemically modified gold surfaces and fluorescently labeled complements to study the hybridization adsorption and enzymatic manipulation of the oligonucleotides.     

The catalytic domain of protein kinase C chimeras modulates the affinity and targeting of phorbol ester-induced translocation

Emerging evidence suggests important differences among protein kinase C (PKC) isozymes in terms of their regulation and biological functions. PKC is regulated by multiple interdependent mechanisms, including enzymatic activation, translocation of the enzyme in response to activation, phosphorylation, and proteolysis. As part of our ongoing studies to define the factors contributing to the specificity of PKC isozymes, we prepared chimeras between the catalytic and regulatory domains of PKCalpha, -delta, and -epsilon. These chimeras, which preserve the overall structure of the native PKC enzymes, were stably expressed in NIH 3T3 fibroblasts. Their intracellular distribution was similar to that of the endogenous enzymes, and they responded with translocation upon treatment with phorbol 12-myristate 13-acetate (PMA). We found that the potency of PMA for translocation of the PKCalpha/x chimeras from the soluble fraction was influenced by the catalytic domain. The ED50 for translocation of PKCalpha/alpha was 26 nM, in marked contrast to the ED50 of 0.9 nM in the case of the PKCalpha/epsilon chimera. In addition to this increase in potency, the site of translocation was also changed; the PKCalpha/epsilon chimera translocated mainly into the cytoskeletal fraction. PKCx/epsilon chimeras displayed twin isoforms with different mobilities on Western blots. PMA treatment increased the proportion of the higher mobility isoform. The two PKCx/epsilon isoforms differed in their localization; moreover, their localization pattern depended on the regulatory domain. Our results emphasize the complex contributions of the regulatory and catalytic domains to the overall behavior of PKC.     

Advances in capillary electrochromatography

Capillary electrochromatography (CEC) is a hybrid between capillary electrophoresis and high performance liquid chromatography (HPLC) that has gained popularity in recent years. CEC uses an electrically driven flow to transport the solutes through the chromatographic column. Separation can be achieved by differential partition between two phases, differential electromigration, or a combination of these two. Herein, the main features of CEC are presented, including basic principles and a literature overview on different practical approaches used.     

A new method for deep reflex muscular massage

As professionals, dentists should continue to learn and improve our skills throughout our careers. Continued competency testing, however, will neither assure nor accurately measure this process. It isn't necessary, won't improve the public's dental health, and would be very expensive.