Biomedical subjects
Publications and source records attributed to R M Torack.
The early life, death, and revival of the concept of cerebral edema are discussed. This unusual sequence has been related to a clinical syndrome, a vascular hypothesis, a unique brain circulation, and a new investigative technique: electron microscopy.
Forty-four patients with Alzheimer's disease were evaluated for delayed hypersensitivity responses using five ubiquitous antigens. Compared with a nondemented age-matched population, these patients evidenced a large number of deficient responses, especially in the zero-response group. Twenty-three patients were randomly selected for immunostimulation using BCG vaccine. The skin tests were repeated 2 weeks after a series of four weekly intradermal injections of BCG. Only 2 of 13 nonresponsive patients failed to convert at least one negative result into a positive response, and seven became normal.
Explore the source record for details and available documents.
A cytochemical study of 14 cases of adult dementia revealed the presence of gamma globulin in the amyloid of three cases of congophilic angiopathy by means of immunofluorescence microscopy. In these cases, the additional identification of human albumin is regarded to indicate a non-specific macromolecular leak in the blood-brain barrier. Both reactions are inhibited by prior absorption with the appropriate serum protein. Twelve of the 14 cases had congophilic amyloid deposits which were not affected by permanganate pre-treatment, so that immunoglobulin content remains a possibility, despite the negative immune reaction. Alcianophilia was studied at a varying pH and electrolyte concentration, but these findings do not appear to have nosologic significance. The three positive cases are characterized by a rapid terminal decline. The heterogeneity of amyloid and the significance of immunoamyloid in the pathogenesis of adult dementia is discussed.
Ultrastructural studies of the subependymal neuropil of the lateral ventricular wall in the adult rat reveal two different types of enlarged extracellular spaces which appear to be due to the presence of glycosaminoglycans. Focal irregular enlargements are more numerous and are distinguished by the presence of fibrillar material. The other network is characterized by uniform width, branching processes, and an electron density identical to vascular basement membranes. The origin of the extracellular material is not revealed by these studies, but a relationship is suggested between the focal dilatation and subependymal cells. The distinction of these spaces is emphasized by the study of neonatal brain and by the use of ruthenium red (RR). Focal dilatations are very prominent in the 10 day old rat, but they do not contain fibrillar material. An adult type basement membrane-like network is present at this time. In the adult rat the focal dilatation has great affinity for RR, but the second network is very sparsely stained. The RR affinity is not present in the 10 day old rat; however, by the 26th day, the affinity is almost as great as that of an adult. These findings are considered to enhance the concept of a separate origin, composition, and probable function of these two networks.
Histochemical studies of normal adult rat brain indicate two types of glycosaminoglycans in the subependymal region of the lateral ventricle. One network is characterized by an affinity for the cationic dyes alcian blue, aldehyde fuchsin and colloidal iron. These reactions occur at pH 1.0 and at 0.5-0.3 M concentration of MgCl2, which suggests that this material is chondroitin sulfate. The other system is identified by metachromasia with toluidine blue and a loss of PAS staining following sulfation. These findings are consistent with non-sulfated and non-anionic acid mucopolysaccharides. In developing rat brain the differential development of these networks enhances their separate identity. The metachromatic network is present at least by the 10th postnatal day but the polyanionic electrolytes cannot be identified until the 16th to the 22nd days. The possible functional importance of these systems is discussed.
Ophthalmoplegia is rarely observed in patients with amyotrophic lateral sclerosis (ALS). We describe a patient with ALS in whom ophthalmoplegia, initially appearing midway in her course, progressed to total paralysis of extraocular movements by the time of death. In addition to the usual postmortem findings of ALS in the brain stem and spinal cord, there was extensive neuronal loss and gliosis involving the caudal portions of the dorsal and intermediate components of the oculomotor nuclei, the caudal part of the trochlear nuclei, and the abducens nuclei. This represents the first detailed report of the findings in the nuclei of cranial nerves III, IV, and VI in a patient with ALS and ophthalmoplegia.
The historical events in the evolution of Alzheimer's disease are reviewed, including the initial description by Alois Alzheimer and the subsequent controversy regarding the nosological specificity of this entity. The similarity of senile dementia and Alzheimer's disease is emphasized. The basis for the modern concept of Alzheimer's disease as premature or accelerated aging is included in the review. The pathological correlates of the major categories of adult dementia have been described. The traditional criteria of neurofibrillary tangles and senile plaques have been re-evaluated using the current insight into these changes afforded by electron microscopy and biochemistry. The significance of amyloid has been described because it occurs within the senile plaque and also as the essential component of congophilic angiopathy. The new information regarding neuronal cell counts and the loss of choline acetyltransferase has been evaluated in terms of an indication of a pathogenic mechanism of Alzheimer's disease. The current understanding of normal pressure hydrocephalus, Creutzfeldt-Jakob disease, and multi-infarct dementia has been described. Brain biopsy in dementia has been described as having diagnostic, research, pathogenic, and prognostic value. The precautions involving the performance and handling of the biopsy have been stressed, particularly because these procedures involve conditions of possible slow virus etiology. The polemic for Alzheimer's disease as aging or slow virus infection has been summarized. At this time a consideration seems justified that Alzheimer's disease is an age-related, slow virus disease due to a hitherto unknown immune defect. Aging as an etiological agent must be clarified before Alzheimer's disease, in any form, can be considered to be an inevitable consequence of longevity.
We correlated the radiologic and pathologic examination of 13 human brains, analyzing the size, different histologic elements, and water content in 40 ischemic and hemorrhagic infarcts. Acute infarcts appear in the computerized cranial tomographic (CT) image as low density areas due to high content of fluid, however, a histological-chemical correlation is not concomitant. The addition of blood in hemorrhagic infarcts may result in a normal CT image. Subacute infarcts appear as low density areas, with lower attenuation values due to the presence of large amounts of lipids. Subacute lesions with prominent mineral deposits may be negative on CT scan. Chronic infarcts also appear as low density areas due to cavitation and residual fats. Attenuation values are slightly higher than those of subacute infarcts, possibly due to gliosis. Infarcts smaller than 2 cm in diameter are usually not visualized.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
An assay of water content and specific gravity in normal and pathological autopsy brain has been correlated with CCT attenuation values obtained just prior to brain cutting. Formalin fixation does not alter normal values so that fixed brain appears to be suitable for this type of study. Low attenuation values in CCT correlate better with changes in specific gravity, rather than water in infarcts, but they have a close relationship to water content in edema. The high water content in infarcts of the white matter reveals a striking disparity in fluid control between cortex and white matter, which has not been emphasized in experimental studies. Water movement within and around blood clots has been discussed.
Retarded mental and motor development was observed during the first year of life of a full-term female who had been delivered with difficulty. Generalized psychomotor seizures and dysplastic "acromegalic" facial changes began to develop when she was 8 years old, and generalized amyotrophy developed over the next several years. The course was generally progressive, and she died at age 31. A variety of clinical laboratory studies were nondiagnostic. Autopsy findings showed normal brain weight and normal-appearing cerebral hemispheres, a peculiar atrophy of the inferior portion of the cerebellar hemispheres, a demyelinating process in the dorsal columns of the cervical and thoracic spinal cord, and lateral column and motor neuron degeneration. The pathogenesis of the syndrome is undetermined.
Three autopsied cases of congophilic angiopathy have been studied by means of polarized light microscopy and in 2 of these, biopsy material is available for electron microscopic study. All 3 patients had a surgical procedure and a subsequent massive hemorrhagic episode. Two of these patients had clinical evidence of dementing syndrome, for which shunts were performed. Ultrastructural studies have confirmed the amyloid nature of the congophilic material in the 2 biopsied cases. The deposition of amyloid in these cases is believed to be a primary event and is related to a generalized body disorder. The distinction of congophilic angiopathy from Alzheimer's disease is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.