Sylvia Pandolfi

Vital staining, serum albumin and the blood-brain barrier.

Vital staining was studied by quantitating the amounts of Evans blue and serum albumin in muscle and in abnormal brain. On the basis of differences in the ratio of dye to albumin in tissue and in serum, it was concluded that the coloration of tissue involves both the presence of serum albumin in tissue and the binding of dye not associated with serum albumin by tissue. The mode of binding of free dye by edematous cerebral tissue was studied by comparing the chemical structures of a series of acid dyes which did and did not function as vital stains. It was concluded that substantivity for edematous cerebral tissue requires the presence on the dye molecule of paired widely separated electron-donating hydrogen bond forming groups placed away from the solubilizing acid groups. It is suggested that the primary mode of binding for Evans blue in tissue is through the formation of hydrogen bonds between the azo groups of the dye and the hydroxy groups of tissue polysaccharides. These findings are conceptually related to the blood-brain barrier in that the presence of staining in the brain reflects the presence of increased amounts of albumin either at the time of observation or at some time in the past.

Furosemide and pentobarbital in cryogenic cerebral injury and edema

The effects of furosemide and pentobarbital on the edema associated with cryogenically-induced cerebral lesions in the rhesus monkey were quantitatively measured. Both drugs caused a decrease in the increments of water, sodium, and chloride in the damaged hemisphere. In addition, the pentobarbital was associated with a decrease in the uptake of serum protein. The effects of the two drugs were not additive. It is proposed that furosemide be given a clinical trial in the treatment of human cerebral edema.

The Chemistry of Isolated Edema Fluid in Experimental Cerebral Injury

Focal areas of hemorrhagic necrosis were produced in the brains of anesthetized dogs by a freezing technique which has been described in previous publications (Clasen, et al., 1953). Briefly, this consisted of the application of a freezing instrument cooled by liquid nitrogen to the exposed intact skull. The instrument was left in place for five–ten minutes. This resulted in a circumscribed lesion involving both gray and white matter in the underlying brain. In the first hour after injury, cellular damage was restricted to the lesion. Four hours after injury, histologic evidence of edema was seen both in the lesion and in the adjacent white matter. Both areas showed positive staining by the periodic acid-Schiff (PAS) technique (Clasen, et al., 1957).

Protein and electrolyte changes in experimental cerebral edema.

Analysis of protein and electrolyte data in cryogenic cerebral edema in the rhesus monkey has led to the conclusion that, in the first 24 hours (h) after injury, the edamatous process is not homogenous, but compartmentalized. This involves, first of all, a division into intra- and extracellular compartments. The intracellular compartment is further divided into a compartment containing water, electrolytes, and serum proteins, and a compartment containing only excess sodium. The extracellular compartment is also subdivided into a compartment containing albumin, globulin, and electrolytes, and a compartment containing only albumin and electrolytes. Anatomically, the latter is most likely the pre-existing normal extracellular space

The Staining of the Myelin Sheath by Luxol Dye Techniques

The basic mechanisms by which luxol fast blue stains myelin sheaths was studied by experiments directed to elucidating the chemistry of the dye, the nature of the substrate, and the mode of binding of the dye to the substrate. The diphenylguanidine salts of a series of acid dyes were synthesized. All functioned as myelin stains demonstrating that the chemical basis of the staining reaction is the fact that luxol fast blue is the diarylguanidine salt of an acid dye and is not related to the specific structure of the dye. The nature of the substrate was investigated by chemical analysis of isolated myelin and tissue sections. It was determined that myelin contains a high proportion of non-polar amino acids and fatty acid residues which are not extractable by lipid solvents. It is suggested that these structures are concentrated in hydrophobic sites in the myelin substrate and that the dye gains access to these by virtue of its water insolubility. The mode of binding was studied by chemical analysis of the diphenylguanidine salt of congo red in its reaction with tissue sections. It was determined that when the dye is bound to the substrate the diphenylguanidine is released. Since with all luxol dyes the shade of the myelin sheath changes following the application of the basic counterstain, it is further proposed that these dyes have a double function in this staining reaction acting as both dyes and mordants.

Computed Tomography of Vasogenic Cerebral Edema

The vasogenic cerebral edema associated with four different types of human lesions was studied by correlating the CT scan with the histologic pattern. The cerebral edema associated with cryogenic lesions in the rhesus monkey, considered to be the prototype of vasogenic edema, was also studied. It was concluded that the areas of diminished density observed around these cerebral lesions represents histologically recognizable cerebral edema. The density of this edematous tissue varied from 11 to 17 H. It was further concluded that these differences in density may be a reflection of the protein content of the edema fluid.

Interrupted hypothermia in experimental cerebral edema

IN A PREVIOUS REPORT it was shown that cerebral edema induced by focal freezing of the brain in monkeys could be effectively treated by sustained systemic hyp0thermia.l This report deals with interrupted hypothermia. Although the present quantitative figures are less decisive than those in the previous report, we have interpreted them as indicating a suppression of both hemorrhage and edema in the damaged hemisphere.

Reserpine in experimental cerebral edema.

THE EXPERIMENTS to be reported represent a continuation of work done on cerebral injury in monkeys. Standard injuries were produced by freezing through the intact skull. This resulted in an area of hemorrhagic necrosis accompanied within four hours by the development of edema in and around the lesion. Efforts were then made through chemical analyses of the damaged tissue to evaluate various forms of therapy designed to alleviate this edema. Previous reports have dealt with intravenous hypertonic urea given six hours after injury1 and steroids given twelve hours after injury.2 The present report deals with reserpine. The rationale for the use of this drug was the report by Bulle3 that cerebral edema, as judged by vital staining, could be induced in mice by the intracerebral injection of serotonin and that this reaction could be suppressed by pretreatment with reserpine. In addition, Levine and associates4 have shown that this type of edema shows a positive reaction with the periodic acid-Schiff (PAS) technique. The edema associated with freezing lesions is strongly PAS positive. In testing the reserpine, the time of sacrifice was increased from twelve to twentyfour hours in order to allow a greater time for possible drug action.

Histopathology and Computerized Tomography of Human Traumatic Cerebral Swelling

Any discussion of cerebral edema must begin with a definition of terms. This relates to the question of whether a fundamental distinction can be drawn between cerebral swelling and cerebral edema, or whether these terms simply describe the gross and microscopic picture of what is essentially the same process (1–3). It has been proposed that a gross distinction can be made between swelling and edema. In the former the cut surface of the brain is dry and in the latter wet. Those holding the opposing view argue that this difference is quantitative, i.e. that the wet brain is more edematous than the dry brain. The resolution of this controversy depends upon the definition of the histopathologic basis of cerebral swelling. This has been a contribution of electron microscopy.

Electron Microscopic and Behavioral Studies in Experimental Lead Encephalopathy

There is much concern that even at the relatively low levels of lead which do not result in acute toxicity, alterations in cognitive function may occur [10]. Impairments in learning following early lead exposure have been reported in a number of species. Ewes were exposed to lead before breeding and throughout gestation [4]. At 4 months of age, the lambs born to them had a mean blood lead level of 14 μg% (control 4.7 μg%). At 5 months, the lambs were taught to discriminate between a circle and a triangle and then among circles of different sizes. The prenatally exposed lambs took significantly longer than controls to learn the size discrimination. This may be interpreted as a defect in reversal learning.