Additional electron microscopic observations on two cases of Batten-Spielmeyer-Vogt disease. (Neuronal ceroid-lipofuscinosis)

Ultrastructural differences impact cilia shape and external exposure across cell classes in the visual cortex

A primary cilium is a membrane-bound extension from the cell surface that contains receptors for perceiving and transmitting signals that modulate cell state and activity. Primary cilia in the brain are less accessible than cilia on cultured cells or epithelial tissues because in the brain they protrude into a deep, dense network of glial and neuronal processes. Here, we investigated cilia frequency, internal structure, shape, and position in large, high-resolution transmission electron microscopy volumes of mouse primary visual cortex. Cilia extended from the cell bodies of nearly all excitatory and inhibitory neurons, astrocytes, and oligodendrocyte precursor cells (OPCs) but were absent from oligodendrocytes and microglia. Ultrastructural comparisons revealed that the base of the cilium and the microtubule organization differed between neurons and glia. Investigating cilia-proximal features revealed that many cilia were directly adjacent to synapses, suggesting that cilia are poised to encounter locally released signaling molecules. Our analysis indicated that synapse proximity is likely due to random encounters in the neuropil, with no evidence that cilia modulate synapse activity as would be expected in tetrapartite synapses. The observed cell class differences in proximity to synapses were largely due to differences in external cilia length. Many key structural features that differed between neuronal and glial cilia influenced both cilium placement and shape and, thus, exposure to processes and synapses outside the cilium. Together, the ultrastructure both within and around neuronal and glial cilia suggest differences in cilia formation and function across cell types in the brain.

Nanometer-scale views of visual cortex reveal anatomical features of primary cilia poised to detect synaptic spillover

A primary cilium is a thin membrane-bound extension off a cell surface that contains receptors for perceiving and transmitting signals that modulate cell state and activity. While many cell types have a primary cilium, little is known about primary cilia in the brain, where they are less accessible than cilia on cultured cells or epithelial tissues and protrude from cell bodies into a deep, dense network of glial and neuronal processes. Here, we investigated cilia frequency, internal structure, shape, and position in large, high-resolution transmission electron microscopy volumes of mouse primary visual cortex. Cilia extended from the cell bodies of nearly all excitatory and inhibitory neurons, astrocytes, and oligodendrocyte precursor cells (OPCs), but were absent from oligodendrocytes and microglia. Structural comparisons revealed that the membrane structure at the base of the cilium and the microtubule organization differed between neurons and glia. OPC cilia were distinct in that they were the shortest and contained pervasive internal vesicles only occasionally observed in neuron and astrocyte cilia. Investigating cilia-proximal features revealed that many cilia were directly adjacent to synapses, suggesting cilia are well poised to encounter locally released signaling molecules. Cilia proximity to synapses was random, not enriched, in the synapse-rich neuropil. The internal anatomy, including microtubule changes and centriole location, defined key structural features including cilium placement and shape. Together, the anatomical insights both within and around neuron and glia cilia provide new insights into cilia formation and function across cell types in the brain.

Neurofibrillary pathology and protein synthetic capability in nerve cells in Alzheimer's disease

Nucleolar volume was measured in nerve cells of the temporal cortex in cases of Alzheimer's disease, obtained at both biopsy and autopsy. Measurements were made on those nerve cells containing neurofibrillary tangles and also on ones free of such changes. Results showed that nucleolar volume is significantly reduced, by at least 40%, in both tangle and non-tangle bearing cells, in both biopsy and autopsy cases, when compared with corresponding values from appropriate control cases. Furthermore, in the autopsy cases, nerve cell nucleolar volume was reduced by a further 30% in tangle bearing cells compared to non-tangle bearing neighbours. No such difference was noted in these cells in the biopsy cases. These findings imply that alterations in protein synthetic capability occur in nerve cells early in the course of Alzheimer's disease, and that this change is not, at least in these initial stages, related to accumulation of neurofibrillary material within the cell body, although later on such accumulation may result in added disruption of cell metabolism.

Nuclear inclusions in Alzheimer's disease

Biopsy samples of parietal cortex from seven patients undergoing atrio-ventricular shunt operations have been examined electron microscopically. Five were suffering from Alzheimer's disease, while two were subjects with normotensive hydrocephalus following previous head injuries. Intranuclear neuronal, inclusions of three types were found. Most frequent was the intranuclear rodlet, which was commonly observed in four of the patients with Alzheimer's disease, but in one block only from one of the hydrocephalus cases. The other two types, namely the spherical inclusion body and the vermicellar-like inclusion, were found less commonly and in only two cases. No inclusions were seen in glial nuclei.

Computed tomography in neuronal ceroid lipofuscinosis

The computed tomography (CT) findings in a verified case of neuronal ceroid lipofuscinosis (NCL) are presented. CT revealed diffuse and severe cerebral atrophy, reflected by generalized subarachnoid space enlargement and symmetric ventricular dilatation. There was no evidence of abnormalities of the white matter. The CT features in our case of NCL correspond perfectly with the neuropathologic changes of the disease mentioned in the literature. Furthermore, CT is of considerable help in differentiating between those inherited metabolic brain diseases characterized primarily by white matter involvement and those presenting predominantly with changes of grey matter.

On the ultrastructural diversity and essence of residual bodies in neuronal ceroid-lipofuscinosis

In 4 patients with neuronal ceroid-lipofuscinoses (NCL) (3 patients with the junvenile type, 1 patient with the late infantile type), the ultrastructural spectrum of residual bodies in the central and peripheral nervous system presented curvilinear profiles in all cases and regions investigated and many more ultrastructural patterns within and beyond regions commonly accessible to biopsy, probably due to age dependence, local tissue and cellular biochemical factors. Sampling from basal ganglia especially yielded combined curvilinear-fingerpint bodies, from peripheral ganglia additional membranous bodies. Residual bodies in NCL were present in almost every cell type, similar to the distribution of regular lipofuscin. Although the classical subgroups of NCL contain electronmicroscopically well defined residual bodies, permitting distinction of the late infantile type from the juvenile type, the ultrastructural differences are more of a quantitative than of a qualitative nature. However, they are not pathognomonic. N.m.r. spectra of ceroid and lipofuscin support the concept of their biochemical similarity, and argue against the proposition that they contain a single major component.

Ultrastructural pathology of lymphocytes in neuronal ceroid-lipofuscinoses

Lymphocytes were studied by electron microscopy in five cases of neuronal ceroid-lipofuscinoses (NCL), one of infantile, three of late infantile and one of juvenile types. Each type of NCL revealed specific cytoplasmic inclusions, namely, granular bodies in the infantile form, curvilinear profiles in the late infantile form and fingerprint profiles within vacuoles in the juvenile type. Survey of the literature also confirmed the high correlation between subtype of NCL and type of lymphocytic inclusion. The electron microscopic examination lymphocytes offers easily available diagnostic informations.

So-called neuronal ceroid-lipofuscinosis. Histochemical study with evidence of extractibility of the stored material

Histochemical study of so-called neuronal ceroid-lipofuscinoses (NCL) showed that the stored material is extractable in the unfixed state especially with alkalized or acidified chloroform-methanol mixtures when compared with other solvents. The extractability was strongly reduced or almost abolished by fixation with formaldehyde. Identical results were obtained with the type one storage material (see Elleder, 1977) in all late infantile cases and in a juvenile case studied, in which, contrary to the infantile form, the stored material displayed a significantly higher degree of extractability. As far as the extractability of the type two storage material is concerned insufficient data have been accumulated, but it seems that it does not differ significantly from the first one. In the control group of lipopigments ceroid was found to be much more extractable under identical conditions than matured lipofuscin which was almost entirely resistant to all extraction procedures. The significance of the results is discussed.

Mental retardation, hypotonia, and generalized seizures associated with astrocytic "residual" bodies. An ultrastructural study

Two siblings suffering since birth from convulsions, hypotonia, and mental retardation are presented. In the older sibling (eight and one-half years of age) frontal lobe biopsy revealed abnormal cytosomes with lamellar profiles in astrocytes, macrophages, and to a lesser degree in neurons. Similar cytosomes have not yet been reported in cases of sphingolipidoses or in late infantile-juvenile amaurotic idiocy. These cytosomes stained intensely with silver proteinate, an ultrastructural cytochemical stain for carbohydrate moieties. In contrast, lipofuscin did not stain with silver proteinate. Multilamellar (crescentic curvilinear) cytosomes from a reported case of late infantile amaurotic idocy (Batten-Vogt-Spielmeyer disease) did not stain with silver proteinate. Abnormal cytosomes were not found in blood cells, liver, and peripheral nerve. In the younger sibling (14 months old) postmortem ultrastructural studies of cerebral tissue showed very few abnormal cytosomes. On the basis of the clinical and ultrastructural findings, we conclude that these two cases can be distinguished from those with multilamellar (crescentic-curvilinear) inclusions and from cases of the so-called "neuronal ceroid-lipofuscinosis" syndrome.

Sea-blue histiocytes and sural nerve in neurovisceral storage disorder with vertical ophthalmoplegia

Ultrastructural investigation of bone marrow histiocytes in neurovisceral storage disorder associated with vertical ophthalmoplegia revealed 3 types of cytosomes: (1) lamellar cytosomes; (2) larger cytosomes composed of lamellar fragments and a granular component; and (3) large irregular cytosomes with amorphous and granular portions, often including fingerprint profiles--in some of these, lysosome-like bodies were numerous. The lamellar cytosomes corresponded to vacuoles seen by light microscopy. The Type 2 and 3 cytosomes were the ultrastructural substract of Wright-Giemsa stained blue granules. Histiocytes having a predominance of Type 2 cytosomes in a cytoplasm rich in free ribosomes had the appearance of sea-blue histiocytes at the light-microscopic level. Transformed Type 1 cytostomes served as building blocks for Type 2 and 3 cytosomes. In the sural nerve, Schwann cells and endoneurial fibroblasts accumulated autofluorescent lipopigment but no lamellar cytosomes or their fragments were found on electron-microscopic examination. Ultrastructure of sea-blue histiocytes in this disease differed from that observed in some other diseases.

Neuronal ceroid-lipofuscinosis, a type of amaurotic family idiocy. Clinical and pathological study of four cases

Neuronal ceroid-lipofuscinosis (NCL) is a recent term, proposed for acurate designation of the late-onset types of Amaurotic Family Idiocy (AFI). Histopathology shows ubiquitous intraneuronal accumulation of lipopigments, being the most important factor for characterization of the entity at present time. Biochemical changes and pathogenesis are obscure. NCL is in contrast to the infantile type of AFI (Tay-Sachs disease), in which intraneuronal accumulation of gangliosides (sphingolipids) is due to the well known deficiency of a lysosomal enzyme. The authors report on four cases of NCL, two brothers of the late infantile (Jansky-Bielschowsky) type and a brother and a sister of the juvenile (Spielmeyer-Sjögren) type. One autopsy and three cortical biopsies revealed moderate to severe distention of the neurons by lipopigment, with nerve cell loss, gliosis and cerebral atrophy. Lipopigment was also increased in liver, heart and spleen. The patients were the first in Brazilian literature in whom the storage material was identified as lipopigment by histochemical methods. A brief summary of the clinical features of NCL is presented, and relevant problems are discussed, concerning interpretation of the nature of the storage material, and significance of the disease for gerontological research.