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Biomedical subjects

B Burns

Publications and source records attributed to B Burns.

At least 73 records · Page 4Linked to original sources
PubMed1975

Pathophysiology of chronic communicating hydrocephalus in dogs (Canis familiaris). Experimental studies.

A model designed to produce chronic communicating hydrocephalus in dogs has been developed in our laboratory. The animals tolerate the procedure well and the yield of animals with communicating hydrocephalus is high. Serial cisternograms show ventricular entry first with "clearing" and later with "stasis". CSF pressures are initially increased, but when the ventricles become enlarged the pressure falls into the normal range. Grossly there is generalized ventricular enlargement and, on histological studies, the ependyma is flattened and denuded. Periventricular edema occurs in the white matter. Autoradiographs show transependymal movement of protein. CSF production appears to be normal despite obstruction to flow of CSF to areas where resorption is greatest. Diversionary shunting probably produces relief of many of the neurological symptoms by providing an efficient pathway for the removal of CSF and thus by lessening edema and ventricular enlargement. A more appropriate treatment would appear to be a noninvasive method of decreasing CSF production. Only when the basic pathophysiological alterations of CSF production and absorption are understood will this be possible. We believe that this animal model affords us the opportunity of studying these mechanisms.

Animals↗
PubMed1975

Physiological evidence consistent with the presence of a specific O2 carrier in the placenta.

In 30 experiments we perfused the fetal side of the sheep placenta with fluids which had different solubilities for argon, N2, and O2 (dextran, blood, and fluorocarbon emulsions). In some of the experiments we partially exchange-transfused the ewe with the fluorocarbon emulsion. By these procedures we were able to change the physical solubility of argon and N2 severalfold in the fetal perfusion fluid and maternal blood. We found that the diffusing capacity for argon and N2 did not increase with increases in physical solubility in the fetal perfusion medium or in maternal blood. This indicated that the rate-limiting step in the placental transfer of these gases is the small diffusing capacity of the placenta. In contrast, O2 diffusing capacity increased markedly with increased solubility in the fetal perfusion medium. Also the Po2 was frequently the same in the venous blood leaving both sides of the placenta. This indicates that O2 may reach equilibrium between maternal and fetal capillaries in one pass through the placenta. The results are compatible with the presence of specific O2 carrier in the placenta.

Animals↗
PubMed1969

Microvolt electric signals from fishes and the environment.

Pulses in the 0.01 to 40 microvolt range, probably generated by white fiber muscle action potentials, were remotely received through dipole antennae from five fishes and one amphibian in aquarium tests. In natural environments, however, no biologically generated signals have been detected. Received instead were a multitude of similar signals originating from unknown sources. The dominant types of these "atmospheric" signals and their reception rates change diurnally and can easily be confused with the fish-generated signals.

Amphibians↗
PubMedDate not supplied

Problems of self-regulation: a new way to view deficits in children born prematurely.

While survival rates for the smallest infants are increasing, so is the rate of disability. Low birth rate children are at increased risk for psychiatric and behavioral symptoms especially those related to attention deficit and hyperactivity disorders. Researchers have demonstrated that even "normal" low birth weight (LBW) children receive special educational services at an alarming rate. Little is understood about the processes responsible for these academic delays. Preventative interventions cannot be implemented without understanding the underlying developmental processes. The study of self-regulation (SR) of cognition and the factors that may influence the development of regulatory capacity are suggested as a way to frame future work. SR of cognition refers to one's ability to select and use information appropriately. Problems in the development of the self-regulation of attention may explain deficits in the acquisition of cognitive skills as well as other deficits. The argument is made that specific variables may directly, indirectly or in both ways influence mechanisms and processes underlying the development of attention in LBW children. It is proposed that studying the SR of cognition provides a potentially useful and powerful focus for intervention research.

Attention Deficit Disorder with Hyperactivity↗