Nicholas K. Gonatas

Superior sensitivity of conjugates of horseradish peroxidase with wheat germ agglutinin for studies of retrograde axonal transport.

We have compared the retrograde axonal transport of horseradish peroxidase (HRP), to the retrograde transport of HRP conjugated with wheat germ agglutinin (WGA). Morphometric studies have shown that WGA-HRP conjugates were 40 times more sensitive than free HRP, in the tracing of retrograde connections from the rat submandibular gland to the superior cervical ganglion. Also, WGA-HRP was more sensitive than free HRP in the tracing of retrograde connections from the rat tongue to the hypoglossal nucleus. Our findings with WGA-HRP are consistent with the observations by Schwab et al. who reported (-125I) WGA is a highly sensitive retrograde tracer (Brain Research 152:145, 1978 (22)).

MHC antigen expression on bulk isolated macrophage-microglia from newborn mouse brain: induction of Ia antigen expression by γ-interferon

Abstract Macrophage-microglia were isolated from primary mixed brain cell cultures of normal newborn mice. They were successfully maintained in vitro for at least 8 weeks. Purity of the cultures was 97–100%, as determined by endocytosis of latex beads, non-specific staining through Fc receptors, EA and EAC rosette formation. These cells were non-specific esterase-positive, but peroxidase-negative. Electron-microscope observations revealed morphological similarities to mature macrophages. Isolated macrophage-microglia seldom incorporated [3H]thymidine in vitro. By means of 51Cr release assay, using monoclonal antibodies against mouse major histocompatibility complex (MHC) antigens and complement, we detected class I MHC (H-2) antigen on unstimulated macrophage-microglia, and both class I and class II (Ia) antigens on γ-interferon-treated cells. These observations suggest possible immunoregulatory functions of macrophage-microglia in the central nervous system, as is characteristics of other cells of monocyte lineage.

HISTOCHEMICAL AND ULTRASTRUCTURAL STUDIES ON HELA CELL CULTURES EXPOSED TO SPINDLE INHIBITORS WITH SPECIAL REFERENCE TO THE INTERPHASE CELL

Mammalian cells of the HeLa (S3) strain, when exposed to spindle inhibitors, have been found to undergo several morphological transformations during interphase as well as during mitosis. Some of these have been studied both histochemically and ultrastructurally. The lysosomes, represented by the multivesicular bodies in HeLa cells, form clusters and become circumferentially disposed instead of occupying the polarized juxtanuclear position characteristic of these organelles. In the electron microscope it is seen that they have acquired a dense osmiophilic core that is separated from the bounding unit membrane by an electron lucent halo. The Golgi apparatus fragments under the influence of spindle inhibitors and also takes up a circumferential distribution in a pattern similar to that of the lysosomes. On the ultrastructural level, no significant modifications in this organelle are seen. Also noted in the interphase cell are numerous 60-80 Å fibrils coursing through the cytoplasm as well as a paucity of spindle our microtubules. A striking similarity has been pointed out between the behavior of the lysosomes in the drugtreated interphase cell and the untreated, normal mitotic cell. A possible explanation of some of the changes noted has been given in terms of an interruption of protoplasmic flow resulting from the disappearance of microtubules.

The contribution of altered synapses in the senile plaque: an electron microscopic study in Alzheimer's dementia.

Recent ultrastructural studies of cerebral biopsies from patients with Alzheimers presenile dementia have elucidated certain morphological features of neurofibrillary changes and of the senile plaque. Terry (1), Kidd (2), and Terry et al. (3) have described in detail the fine structure of the neurofibrillary change and of the senile plaque which they found to be composed of an extracellular core of fibrils, resembling amyloid, surrounded by cytoplasmic processes containing fibrils, multilnmcllar bodies, and mitochondria. Kidd has also observed dendritic, post-synaptic processes filled with abnormal neurofibrils (helices); Krigman et al(4) have noticed enlarged presynaptic endings containing dense bodies, while Luse and Smith (5) indicated that in the region of the senile plaque, the axon terminals are enlarged and contain “abnormally large and dense vesicles” and fibrils. These findings have been confirmed in the present study. In addition, changes in axons, pre-synaptic and post-synaptic endings, and dendrites, in or around senile plaques, not heretofore reported, have been noted. These findings may be significant in view of the proven role of synapses in establishing functional contacts between neurons and the suggested implication of synapses in learning and memory storage (6–9).

ULTRASTRUCTURAL AND BIOCHEMICAL OBSERVATIONS ON A CASE OF SYSTEMIC LATE INFANTILE LIPIDOSIS AND ITS RELATIONSHIP TO TAY-SACHS DISEASE AND GARGOYLISM.

1. Electron microscopic and biochemical data in a case of systemic infantile lipidosis and in a case of gargoylism have been presented. 2. In the case of systemic late infantile lipidosis, brain gangliosides were elevated, and thin-layer chromatography and analytical studies revealed a predominance of the G4 fraction. Numerous membranous cytoplasmic bodies (MCB) and large lysosomes were found. Significant differences from Tay-Sachs disease, juvenile lipidosis, and gargoylism have been pointed out, justifying the classification of this case as a separate entity. 3. In the case of gargoylism, elevation of brain gangliosides (G5 and G6) and acid mucopolysaccharides has been documented. Membranous cytoplasmic bodies were noted in formalin fixed tissue.

Genetic Control of Susceptibility to Experimental Allergic Encephalomyelitis in Rats

Rats of the inbred strains Lewis and DA are highly susceptible to the induction of experimental allergic encephalomyelitis (EAE) while Brown Norway rats are resistant to this disease. Evidence has been obtained which suggests that a single dominant gene is associated with susceptibility to EAE. The locus controlling EAE susceptibility is closely linked to the Ag-B histocompatibility locus but is not identical to it.

A noninvasive protocol for anterior temporal lobectomy

We report the results of a protocol for choosing candidates for temporal lobectomy using a standard battery of objective tests without intracranial electrodes. We assigned each test a level of importance, and an algorithm was used to determine whether temporal lobectomy could be performed. Fifty-one patients (total pool, 103 patients) met protocol requirements and had an anterior temporal lobectomy with a mean follow-up of 39.4 months (range, 21 to 64 months), most remaining on anticonvulsant therapy. Eighty percent are seizure free, 12% have <3 seizures per year or only nocturnal seizures, and 8% have >80% reduction in seizure frequency. One-third of patients who failed protocol criteria did not have temporal lobe seizures when studied with intracranial electrodes. We analyzed and modified the algorithm after comparing these patients with others who were poor candidates for temporal lobectomy. We conclude that this protocol is effective and recommend using such an objective algorithm.

Inhibition of Experimental Allergic Encephalomyelitis in Rats Severely Depleted of T Cells

Lewis rats depleted of thymus-derived cells (B rats) failed to develop either experimental allergic encephalomyelitis or antibody against myelin basic protein. Lewis B rats reconstituted with 690 x 106 thymocytes developed experimental allergic encephalomyelitis and levels of antibody against myelin basic protein comparable to those of controls. The Lewis B rat model should be useful in the analysis of the role of thymus-derived cell populations and antibody in the induction of experimental allergic encephalomyelitis.

Immunocytochemical study of the glial fibrillary acidic protein in human neoplasms of the central nervous system

The distribution of the glial fibrillary acidic protein (GFAP) was investigated in sections of 131 paraffin-embedded brain neoplasms obtained at surgery or at autopsy. The unlabeled antibody immunoperoxidase (peroxidase-antiperoxidase, PAP) method was used. Equally good results were obtained from 17-year-old material and from recent material derived at surgery or autopsy and fixed with Bouin fluid or phosphate-buffered formalin. The perikaryons and processes of reactive astrocytes showed the most intense stain for GFAP. Positive reaction to antibody against GFAP of varying intensity was demonstrated in astrocytomas of various grades of malignancy (32 of 32), glioblastoma multiforme (10 of 10), subependymal giant cell astrocytoma (1 of 1), ependymoma (2 of 10), subependymoma (4 of 4), and astrocytes in mixed neoplasms (8 of 8). In two neoplasms diagnosed as malignant astrocytomas and in four neoplasms diagnosed as glioblastoma multiforme, GFAP stain was limited to a few neoplastic cells. Usually the stain was more intense over processes than in perikaryons, with the exception of gemistocytic astrocytomas and the giant cells in glioblastoma multiforme, which showed an equally intense stain over perikaryons and processes. The periphery of Rosenthal fibers was intensely positive for GFAP. In astrocytic neoplasms the number of GFAP-positive cells and the intensity of the stain were inversely proportional to the degree of malignancy. In the following neoplasms the reaction for GFAP was negative: oligodendroglioma (3), oligodendroblastoma (1), medulloblastoma (3), medulloepithelioma (1), neuroblastoma (1), pineocytoma (1), typical teratoma of the pineal (1), fibrosarcoma (1), pituitary adenoma (2), craniopharyngioma (1), chordoma (1), chemodectoma of globus jugulare (1), metastatic carcinoma (17), and lymphoma (8). In one of 18 meningiomas, endogenous peroxidase activity was seen in mast cells. All meningiomas studied were negative for GFAP. In one of six neurinomas a positive reaction for GFAP was detected over processes. The authors concluded that the immunostain for GFAP is useful in the diagnoses of astrocytic neoplasms and of mixed gliomas.

Glue sniffer's neuropathy

Progressive sensorimotor neuropathy developed in two patients exposed to prolonged (chronic) inhalation of n-hexane (glue sniffing). Sural nerve biopsies showed loss of axons; remaining axons were either normal or showed accumulation of filaments of 90 to 100 A thick, widened nodes of Ranvier, and focal enlargements. The muscle biopsy revealed neurogenic atrophy. Intramuscular nerve twigs and end-plates, studied in one patient, showed loss of axons and nerve terminals. Unmyelinated axons also showed accumulation of 90 to 100 A thick filaments. The similarities between the pathologic findings in the peripheral nerve of these patients and those with acrylamide neuropathy suggest that the n-hexane inhalation produces a dying back neuropathy.