J.M.B.V. de Jong

Metallothionein immunoreactivity is increased in the spinal cord of patients with amyotrophic lateral sclerosis

Sections of the spinal cord from 10 patients with classic amyotrophic lateral sclerosis and from 10 control cases were examined by immunocytochemical methods to localize metallothionein. Metallothionein immunoreactivity was seen in the nucleus and cytoplasm of a subset of astrocytes, largely confined to the gray matter. Also, diffuse gray matter staining was observed, probably representing small glial fibers. Astrocytic metallothionein immunoreactivity (P less than 0.01) and strong gray matter matrix staining (P less than 0.03) was increased in the spinal cords from patients with amyotrophic lateral sclerosis. Although compatible with induction by metals, increased metallothionein expression in the spinal cords from patients with amyotrophic lateral sclerosis may also have resulted from inflammation or gliosis.

Animal models of amyotrophic lateral sclerosis and the spinal muscular atrophies

Abstract The causes of human amyotrophic lateral sclerosis (ALS) and the spinal muscular atrophies (SMA) are, almost without exception, unknown. This ignorance has stimulated the search for animal models to obtain insight into the etiology, pathogenesis and biochemical mechanisms underlying the human disorders. None of the 38 animal models, described in this review, provides an exact animal copy of a specific human motor neuron disease. Most of the models reproduce certain structural or physiological aspects of their human counterparts. The various experimental models can be classified according to the pathogenetic mechanism involved and according to the structural changes observed. Models based on experimentally induced disease, include heavy metals and trace elements (lead intoxication in guinea pigs, rabbits, rats, cats and primates; mercury intoxication in rats; aluminium intoxication in rabbits; swayback in goat kids; calcium and magnesium deficient rabbits and primates and calcium deficient cynomolgus monkeys), toxins (IDPN, vincristine, vinblastine, podophyllotoxin, colchicine, maytansine, maytanprine, l -BMAA, lectins, adriamycin), nutritional factors (ascorbic acid deficient guinea pigs), virus infection (spongiform polioencephalomyelitis, attenuated poliovirus, lactate dehydrogenase-elevating virus), and immunological factors (immunization with motor neurons). Hereditary models comprise hereditary canine spinal muscular atrophy, hereditary neurogenic amyotrophy in the pointer dog, Stockard paralysis, Swedish Lapland dog paralysis, “wobbler” mouse, “shaker” calf, and hereditary spinal muscular atrophy in zebra foals, crossbred rabbits, and Yorkshire pigs. Unknown is the pathogenesis of sporadic SMA in the domestic cat. Models with involvement of the upper motor neuron include swayback, calcium-deficient cynomolgus monkeys, l -BMAA intoxicated monkeys, ascorbic acid-deficient guinea pigs, Swedish Lapland dog paralysis, and the “shaker” calf model.

Localization of metallothionein in the mammalian central nervous system.

This review concerns the immunohistochemical localization of metallothionein (MT), a metal-binding protein, in the mammalian central nervous system (CNS). Expression of MT in the mammalian CNS is abundant. In the mouse brain, MT expression is found in some glial cells, whereas in the adult rat brain immunoreactivity varies from no expression at all to abundant reactivity throughout the whole brain. In primates and humans, MT expression is mainly found in astrocytes. Thus, MT expression in the mammalian CNS is found in the pia-arachnoid, ependymal cells and astrocytes. Cells expressing MTs can, in this way, supply essential metals to neurons and may protect neurons against toxic ions.

Evidence against increased oxidative stress in fibroblasts from patients with non-superoxide-dismutase-1 mutant familial amyotrophic lateral sclerosis

Fibroblasts were cultured from 5 unrelated familial amyotrophic lateral sclerosis (FALS) patients and from healthy control subjects. In parallel, fibroblasts were examined for signs of abnormal oxidative stress by study of reactive oxygen species metabolism and, concurrently, leukocyte DNA from the same patients was examined for superoxide dismutase 1 (SOD1) mutations. The endogenous production of reactive oxygen species was assessed by following the menadione-induced reduction of oxidized cytochrome o, added to the medium. FALS and control fibroblasts exhibited the same rate of metabolism. Also levels of thiobarbturic-acid-reactive species (TBARS), a marker of lipid peroxidation, were similar in fibroblasts from either group. The search for SOD1 mutations by linkage study and cycle sequencing proved negative. We did not find evidence for SOD1 mutations by either method of study. Our results provide no evidence for increased oxidative stress in fibroblasts from non-SOD1 mutant FALS.

A dystrophy-like myopathy in thyroidectomized rabbits

Abstract The histopathological and enzyme histochemical changes in the muscles of thyroidectomized rabbits are described. Between 4 and 18 months after thyroidectomy, the muscles were found to show changes reminiscent of muscular dystrophy, e.g. marked variation in fibre diameter, rounding of fibres, central migration of nuclei, vesicular nuclei with prominent nucleoli, sarcoplasmic masses and, in the later stages, a marked increase in connective tissue and a moderate increase in adipose tissue. Enzyme histochemical changes were also significant, both with oxidative and with glycogenolytic enzymes. Sarcoplasmic masses have been produced experimentally in the muscles of thyroidectomized rabbits.

Plasma creatine phosphokinase study in thyroidectomized rabbits and effect of thyroxine and analogues.

Abstract Thyroidectomy was followed in eleven of fourteen surviving rabbits by an increase in plasma creatine phosphokinase activity, followed after some time by a spontaneous decrease. Normal CPK activity in control rabbits was 0.2–1.7 mU/ml (determination without addition of glutathione) and 2.5–11.2 mU/ml (with addition of glutathione). CPK activity in thyroidectomized rabbits was 0.4–31.6 mU/ml (determination without addition of glutathione) and 3.8–140 mU/ml (with addition of glutathione) but was in at least at one time higher than 20 mU/ml in eleven of fourteen animals. This increased plasma CPK activity can be rapidly normalized by subcutaneously injected 3:5:3′-triiodo- l -thyronine 3:5:3′: 5′-tetraiodo- l -thyronine (= l -thyroxine) and by the thyroxine analogue 3:5:3′:5′-tetraiodothyropropionic acid (= desaminothyroxine) but 3:5:3′-triiodo- d -thyronine is much less effective than its l -form.

Attempted treatment of motor neuron disease with N-acetylcysteine and dithiothreitol.

N-acetylcysteine (NAC) and Dithiothreitol (DTT), two compounds that prevent experimental amyotrophic lateral sclerosis (ALS) in the vitamin C - deficient guinea pig[1], were given to patients with motor neuron disease (MND). These patients were accepted regardless of the stage of their illness, promised uninterrupted treatment, instructed to come for monthly out-patient visits, forbidden the use of the NAC-antagonists phenacetin and acetaminophen and left free to continue any other mode of attempted therapy.

Increased T3 deiodination in dystrophic and neonatally denervated mouse muscle

Abstract T3, free iodide levels and morphological features were compared in normal, 129 ReJ dy/dy dystrophic and neonatally denervated skeletal muscles of mice, killed 6 hr after a single intraperitoneal injection of iodine-labelled hormone. Both the dystrophic and the denervated muscles were found to contain equal amounts of T3 but more iodide than the normal specimens. Increased iodide levels are considered to reflect augmented T3-catabolism by muscle dehalogenase and may indicate low free hormone levels in the soluble enzyme fraction of the cell, despite its normal overall T3 content. The close light-microscopic resemblance of 129 ReJ dy/dy dystrophy and neonatal denervation is confirmed. The possibility is discussed that one or several of the muscular dystrophies are forms of target organ hypothyroidism.