A comparative immunocytochemical study of human cerebellar cortex in X-chromosome-linked copper malabsorption (Menkes' kinky hair disease) and granule cell type cerebellar degeneration

Disorders of metal metabolism

Trace elements are chemical elements needed in minute amounts for normal physiology. Some of the physiologically relevant trace elements include iodine, copper, iron, manganese, zinc, selenium, cobalt and molybdenum. Of these, some are metals, and in particular, transition metals. The different electron shells of an atom carry different energy levels, with those closest to the nucleus being lowest in energy. The number of electrons in the outermost shell determines the reactivity of such an atom. The electron shells are divided in sub-shells, and in particular the third shell has s, p and d sub-shells. Transition metals are strictly defined as elements whose atom has an incomplete d sub-shell. This incomplete d sub-shell makes them prone to chemical reactions, particularly redox reactions. Transition metals of biologic importance include copper, iron, manganese, cobalt and molybdenum. Zinc is not a transition metal, since it has a complete d sub-shell. Selenium, on the other hand, is strictly speaking a nonmetal, although given its chemical properties between those of metals and nonmetals, it is sometimes considered a metalloid. In this review, we summarize the current knowledge on the inborn errors of metal and metalloid metabolism.

The chromosome 16q-linked autosomal dominant cerebellar ataxia (16q-ADCA): A newly identified degenerative ataxia in Japan showing peculiar morphological changes of the Purkinje cell: The 50th Anniversary of Japanese Society of Neuropathology

The chromosome 16q22.1-linked autosomal-dominant cerebellar ataxia (16q-ADCA) is a form of spinocerebellar ataxia (SCA) common in Japan. It is clinically characterized by late-onset purely cerebellar ataxia. The neuropathologic hallmark of 16q-ADCA is degeneration of Purkinje cells accompanied by an eosinophilic structure which we named "halo-like amorphous materials". By immunohistochemistry and electron microscopy, the structure has been so far found to contain two components: the somatic sprouts from the Purkinje cells and presynaptic terminals of unknown origin. As far as we are aware, this peculiar morphological change of Purkinje cells has not been previously described. Further investigations may disclose unique pathological processes in SCA.

Synaptophysin expression in the anterior horn of Werdnig-Hoffmann disease

This report concerns the study of synaptophysin (SP) expression in the anterior horn in four cases of Werdnig-Hoffmann disease (WHD). All patients had distinct anterior horn cell degeneration, and died before the age of one year. Normal spinal cords from five age-matched children served as controls. Five cases of sporadic amyotrophic lateral sclerosis (S-ALS), three cases of lower motor neuron disease (L-MND), three cases of peripheral neuropathy with axonal reaction, and six adult cases with normal spinal cords were included for comparison. Immunohistochemical techniques were used throughout. The results show that normal spinal cords of children have similar SP immunoreactivity patterns as those of normal adults. We also found that despite relatively preserved or slightly increased SP immunoreactivity on the surface of the cell body and proximal processes of the remaining neurons, there was a diffuse decrease of immunoreaction product deposits in the anterior horn neuropil of the WHD cases. The ballooned neurons in the anterior horns of patients with WHD, S-ALS, L-MND, and axonal reaction had few SP immunoreactive dots or granules around the cell bodies and proximal processes. The perikarya of some ballooned neurons of the children with WHD was diffusely stained for SP. There was no SP immunoreactive structures within the empty cell beds of these patients. The observed decrease in SP expression around ballooned neurons in these disorders is indicative of a disconnection of presynaptic terminals of afferent fibers from the proximal portion of the swollen degenerated anterior horn cells.

Synaptophysin expression in the human spinal cord. Diagnostic implications of an immunohistochemical study

Surface perikaryal labeling on immunohistochemical assay for synaptophysin (SYN)--a glycoprotein component of synaptic vesicle membranes--has been posited to distinguish the neoplastic neuronal elements of gangliogliomas from native central nervous system neurons overrun by gliomas invasive of gray matter. To assess the validity of this criterion in the evaluation of intramedullary neoplasms, we screened formalin-fixed, paraffin-embedded sections from 35 histologically unremarkable spinal cords (removed at autopsy) using commercially available monoclonal antibodies to SYN. All specimens exhibited anti-SYN reactivity, which was confined to gray matter, and all evidenced the concentrated deposition of reaction product along the perikarya of large neurons in the anterior horns, Clarke's columns, and intermediolateral cell columns. A majority (23 specimens) contained neurons completely outlined by reaction product rings comparable to those depicted as being pathognomonic of neuronal neoplasia. This phenomenon presumably reflects the rich complement of axosomatic synapses documented in fine structural studies of the normal spinal cord. Surface perikaryal labeling for SYN is not restricted to the neoplastic neurons of ganglion cell tumors and should be cautiously interpreted, particularly when neurosurgical material derives from the spinal cord.

Cytochrome C oxidase deficiency and neuronal involvement in Menkes' kinky hair disease: immunohistochemical study

Antibodies against subunits II and IV of cytochrome c oxidase (COX) and against complex III of the respiratory chain were used to study the expression of these proteins in the cerebellum, spinal cord, and other regions of the central nervous system in an autoptic case of Menkes' kinky hair disease (MKHD). We found a reduced expression of COX subunits in all examined areas whereas staining for complex III appeared normal. Immunostaining was altered in morphologically well-preserved neurons, suggesting that COX deficiency may have a pathogenetic role in the neuronal degeneration of MKHD.

Distinct neuronal subset reveals perikaryal immunostaining for synaptophysin (protein p38) in the striatum of rats

An immunoperoxidase technique was used to locate synaptophysin (protein p38), a major integral membrane glycoprotein of synaptic vesicles, in the rat brain. In addition to a diffuse distribution of nerve terminal stainings for synaptophysin appearing as numerous small puncta, the large-sized cells with spindled or polygonal shapes revealed perikaryal staining for synaptophysin in the striatum. The double labeling with immunofluorescence technique disclosed that the cell bodies, immunoreactive for synaptophysin, appeared to be those of the striatal giant cholinergic neurons. In addition, in rats that underwent the transient middle cerebral artery occlusion, the striatal ischemic lesions with cell type-specific injury revealed a survival of synaptophysin-positive large cells, presumably identical with the cholinergic neurons. The present study suggests that the metabolism and/or axonal transportation of synaptophysin of the giant cholinergic cells may be different from those of other neuronal populations in the striatum. Also, synaptophysin can act as a neurochemical marker for identification of the giant cholinergic neurons in the striatum of rats.

Neuronal protein NP185 is developmentally regulated, initially expressed during synaptogenesis, and localized in synaptic terminals

Evidence is presented here that demonstrates the presence of NP185 (AP3) in neuronal cells, specifically within syn-aptic terminals of the central nervous system and in the peripheral nervous system, particularly in the neuro-muscular junction of adult chicken muscle. Biochemical results obtained in our laboratories indicate that NP185 is associated with brain synaptic vesicles, with clathrin-coated vesicles, and with the synaptosomal plasma membrane. Also, NP185 binds to tubulin and clathrin light chains and the binding is regulated by phosphorylation (Su et al., 1991). Based on these properties and the data reported here, we advance the postulate that NP185 fulfills multiple functions in synaptic terminals. One function is that of a plasma membrane docking or channel protein, another of a signaling molecule for brain vesicles to reach the synaptic terminal region, and a third is that of a recycling molecule by binding to protein components on the lipid bilayer of the synaptic plasma membrane during the process of endocytosis. In support of these premises, a thorough study of NP185 using the developing chick brain, adult mouse brain, and chicken straited muscle was begun by temporally and spatially mapping the expression and localization of NP185 in evolving and mature nerve endings. To achieve these objectives, monoclonal antibodies to NP185 were used for immunocytochemistry in tissue sections of chicken and mouse cerebella. The distribution of NP185 was compared with those of other cytoskeletal and cytoplasmic proteins of axons and synapses, namely synaptophysin, vimentin, neurofilament NF68, and the intermediate filaments of glial cells (GFAP). The data indicate that expression of NP185 temporally coincides with synaptogenesis, and that the distribution of this protein is specific for synaptic terminal buttons of the CNS and the PNS.

Menkes' kinky hair disease: morphological and immunohistochemical comparison of two autopsied patients

An autopsied patient with Menkes' kinky hair disease, who showed unusually long survival until the age of five years with typical neuropathological changes, was examined for distribution of neuronal depletion in the cerebral cortex, and the cerebellar changes were compared morphologically and immunohistochemically with those found in a younger patient (1 year 8 months old) reported previously. Neuronal loss in the cerebral cortex in the both cases, which was ill-defined and unassociated with gliosis, was preferentially distributed in the fifth and sixth layers, especially of the gyral bottom in almost all lobes in the older case. Therefore, this change was thought to be secondary to local ischemia caused by mechanical distortion at the stage of gyrus formation in addition to abnormal development. Ultrastructurally, a prominent increase of confronting cisternae (CC) complexes was found in the perikaryon and processes of Purkinje cells in both cases, and in the older patient CC complexes were arranged more densely and were transformed into concentric lamellar structures in the swollen dendrites. Immunohistochemically, the stainability of neurofilaments (NF, 200 kDa) in Purkinje cells, with or without somatic sprouts was faint or negative in the older patient compared with the marked or moderate positivity in the younger patient and age-matched controls. Empty baskets were absent and NF-positive axonal terminals and synaptophysin-positive granules on Purkinje cells were markedly decreased in both cases. These changes suggest that Purkinje cells degenerate progressively with time and that basket cells also are simultaneously involved.

Immunohistochemical evidence for the selective involvement of dorsal root fibres in Friedreich's ataxia

An immunohistochemical study was carried out in order to elucidate the selective involvement of the dorsal root fibres from two patients with Friedreich's ataxia in comparison with those of 10 neurologically normal control individuals. For this purpose, antibodies to substance P and to synaptophysin were used. Substance P-immunoreactive unmyelinated fibres forming a dense network in the normal substantia gelatinosa of the spinal dorsal horn predominantly originate from a subpopulation of small cells of the dorsal root ganglia, while synaptophysin is present in virtually all nerve cell axon terminals and is useful for visualizing axon terminals in the nervous system. Strong substance P-like immunoreactivity was seen in the substantia gelatinosa of patients with Friedreich's ataxia. By contrast, there was marked depletion of synaptophysin immunoreactivity in the posterior column nuclei, with the gracile nucleus showing greater loss of positive puncta than the cuneate nucleus.

Synaptophysin expression in the striatum in Huntington's disease

This immunohistochemical study compares the expression of synaptophysin (SYP) in the striatum in Huntington's disease (HD) with that of calcineurin (CaN), a marker for striatal medium-sized spinous neurons. As compared to controls, in the HD striatum there was a significant loss of SYP immunoreactivity with residual staining displaying an inhomogeneous pattern, which strikingly resembled that of CaN. Our results may indicate that there is a synaptic loss in the striatum with HD and this is most likely due to loss of medium-sized spinous neurons characteristic of this disease.

Calcineurin and synaptophysin in the human spinal cord of normal individuals and patients with familial dysautonomia

This report concerns the immunohistochemical demonstration of two neuronal Ca2(+)-binding proteins, calcineurin and synaptophysin, in the spinal cord of normal controls and from patients with familial dysautonomia. In controls, calcineurin immunoreactivity was highly concentrated in small nerve cells and fibers of the substantia gelatinosa. Synaptophysin immunoreactivity was normally distributed throughout the spinal cord gray matter, being highly concentrated in the substantia gelatinosa, the dorsal nucleus of Clarke and the anterior horn. In patients with familial dysautonomia, no apparent changes in calcineurin immunoreactivity were found in the substantia gelatinosa. By contrast, there was a significant depletion of synaptophysin-positive axon terminals in the substantia gelatinosa and in the dorsal nucleus of Clarke of patients with familial dysautonomia.