Yuzo Iwasaki

Low energy levels in thiamine-deficient encephalopathy.

Pyrithiamine-induced acute thiamine-deficient encephalopathy was produced in adult male Wistar rats. Twenty-four hours before the onset of neurological signs the brain showed no morphological abnormalities. Encephalopathic rats had symmetrical lesions of edematous necrosis localized in the thalamus, mammillary body, and pontine tegmentum. Biochemically, encephalopathic rats had brain thiamine levels less than 20% of controls. For the assay of the concentrations of adenosine triphosphate (ATP) and phosphocreatine, the brains were fixed using 5 KW microwave irradiation and were divided into four parts: cerebral cortex, diencephalon, lower brainstem, and cerebellum. In the lower brainstem of the encephalopathic rats ATP concentrations were 89.5% of normal controls. Phosphocreatine levels were lowered to 70% of controls in the diencephalon and to 75% in the lower brainstem. Total high energy phosphate levels were decreased to 89% of controls in the diencephalon and 91% in the lower brainstem before the onset of neurological signs and to 76% and 79%, respectively, after the onset. In the cerebral cortex and cerebellum high energy phosphates were not significantly reduced. Lower high energy phosphate levels and the distribution of edematous lesions were coincident in the brain. These findings suggest that a low energy state is closely related to the formation of edematous lesions in thiamine-deficient encephalopathy.

IDENTIFICATION OF THE NORMAL MICROGLIAL POPULATION IN HUMAN AND RODENT NERVOUS TISSUE USING LECTIN–HISTOCHEMISTRY

Identification of the normal microglial population in human and rodent nervous tissue using lectin–histochemistry

Shy-Drager syndrome and amyotrophic lateral sclerosis ☆: Cytoarchitectonic and morphometric studies of sacral autonomic neurons

In order to elucidate the morphological correlates of bladder-rectal dysfunctions in Shy-Drager syndrome, the sacral spinal cord was cytoarchitectonically studied and 3 groups of sacral motor neurons, the posterolateral motor neuron column (PL), inferior intermediolateral nucleus (IML) and cell group X of Onuf (Onuf), were morphometrically quantitated at the S3 level (5 cases), after which the results were compared with those from amyotrophic lateral sclerosis (5 cases) and an age-matched control group (4 cases). The sacral autonomic preganglionic nucleus of IML was localized chiefly in the S3-4 segments and was maximally developed in the caudal one-third of S3. The cell group X of Onuf was localized between the middle of S2 and the rostral one-third of S3 as a longitudinal slender column in the ventral horn. Between these two nuclei at the rostral S3 level, a connecting cellular bridge of neurons of intermediolateral cell type was identified. Morphometry disclosed a marked deprivation of IML, Onuf and somatic motor neurons in Shy-Drager syndrome and a severe loss of somatic motor neurons and a modest deprivation of IML neurons in ALS. These results imply that these two disorders distinguished by different clinical manifestations share a common loss of somatic motor and parasympathetic motor neurons at least in the sacral cord. There are, however, certain gradients in the severity of involvement in these heterogeneous cell groups.

Neuro-Sweet disease Clinical manifestations and criteria for diagnosis

Background: Sweet disease, also known as acute febrile neutrophilic dermatosis, is a multisystem inflammatory disorder characterized by painful erythematous plaques and aseptic neutrophilic infiltration of various organs. Skin biopsies typically demonstrate dermal infiltration with neutrophils in the absence of vasculitis. Sweet disease responds to systemic corticosteroids. The CNS can also be involved. Methods: The authors performed a survey on neuro-Sweet disease (NSD) in Japan and obtained detailed information about 16 cases. They analyzed 42 cases, including 26 cases documented in the literature, and assessed clinical and laboratory criteria for the diagnosis. Results: Thirteen cases also fulfilled the criteria for the diagnosis of Behçet disease. The clinical features of 27 cases, which the authors classified as probable NSD, are as follows: 1) both sexes are almost evenly affected; 2) people of ages 30 to 70 years are affected; 3) encephalitis and meningitis are common neurologic manifestations; 4) any region of the CNS can be involved, resulting in a variety of neurologic symptoms; 5) there is a strong human leukocyte antigen-Cw1 association; 6) systemic corticosteroids are highly effective for most of the neurologic manifestations, although recurrences are not infrequent. Conclusions: Neuro-Sweet disease is a distinct entity that may account for some cases of idiopathic encephalomeningitis.

Retrograde Adriamycin Sensory Ganglionectomy: Novel Approach for the Treatment of Intractable Pain

Selective sensory ganglionectomy by means of retrograde suicide transport of adriamycin was performed on 3 patients with neuropathic pain in the areas of the trigeminal and intercostal nerves, producing significant pain relief, particularly from hyperalgesic pain. Adriamycin ganglionectomy is considered as a less invasive and highly selective pain treatment, which may possibly become an alternative for surgical ganglionectomy or rhizotomy.

Edematous necrosis in thiamine-deficient encephalopathy of the mouse

Acute encephalopathy was produced in the adult male Swiss mouse by pyrithiamine injection in conjunction with a thiamine-deficient diet. The condition of some mice was reversed within 24 hours by a treatment of a high dose of thiamine. The lesions occurred selectively in the thalamus, pontine tegmentum, and mammillary body and were manifested by hemorrhage and edematous necrosis consisting of severe edema of astrocytes, myelin sheaths, and neuronal dendrites. Before thiamine treatment, these degenerative changes were not associated with any mesenchymal reaction. At 48 and 96 hours after thiamine treatment, these edematous changes persisted. Fat-laden macrophages appeared in the lesion. Some axons showed Wallerian-type degeneration. After three weeks of thiamine treatment, macrophages became thin and rod-shaped. Wallerian-type degeneration and myelin edema persisted. The oligodendrocytes and astrocytes were hypertrophic. These lesions of thiamine-treated encephalopathy of the mouse closely resembled the non-hemorrhagic lesions of human Wernicke encephalopathy. Mice which were concomitantly-induced with hyperglycemia and encephalopathy showed no significant differences in clinical and morphologic manifestations from the encephalopathic mice with normal blood sugar levels. Vascular permeability to horseradish peroxidase was increased only slightly at the initial stage, but was reversed in the mice which clinically responded quickly to thiamine treatment. Occasionally, persistent increase of permeability was seen in 21-day-old lesions. These findings suggested that, in thiamine-deficient encephalopathy, both nervous and vascular components in the brain were involved and that the morphologic manifestations of the nervous component were far more extensive than those of the blood vessels.

Retrograde axoplasmic transport of Adriamycin An experimental form of motor neuron disease

Adriamycin (ADM) is a DNA-directed RNA inhibitor. In attempts to produce an experimental form of motor neuron disease, we injected the agent into rat sciatic nerve. Retrograde axoplasmic flow conveyed ADM into soma of the spinal motor neurons, as confirmed by fluorescence microscopy. Motor neuron degeneration, which included nuclear heterochromatinization and diffuse chromatolysis, was observed after 6 to 8 days. After 2 weeks, many neurons that gave rise to sciatic nerve efferents underwent dissolution. Retrograde axoplasmic flow and DNA-injurious substances could affect survival of motor neurons.

Intraneuronal laminin-like molecule in the central nervous system: demonstration of its unique differential distribution

Laminin, an extracellular matrix glycoprotein rich in basement membrane, is a multifunctional molecule of approximately 1000 kDa and is known to possess a potent neurotrophic activity. Laminin-like immunoreactivity (LLI) was for the first time demonstrated in mouse and rat CNS neurons by a sensitive immunohistochemical technique. Transblotting of SDS-PAGE of the supernatant of the mouse and rat brain homogenate identified distinct 180 kDa and weak 380 kDa bands immunoreactive to anti-laminin and these molecules differed from authentic laminin subunits. The intraneuronal distribution of LLI disclosed two distinct patterns; LLI-1 (diffuse perikaryal stain) and LLI-2 (coarse granular stain). By immunoelectron microscopy, LLI was localized to the ERs in LLI-1 neurons, whereas it appeared to be confined to lysosomes in LLI-2 neurons. LLI-1 neurons were found predominantly in hippocampal pyramidal, granule and neocortical layers 1-3, 6 neurons, in most of the striatal and thalamic neurons, and Purkinje cells. The majority of neurons in neocortical layers 4-5, medial septal and Meynert neurons, somatic motor neurons, and neurons of the deep cerebellar nuclei were classified as LLI-2 cells. No LLI was found in hypothalamic mammillary, habenular and vagal dorsal motor neurons (LLI-3). These observations may indicate intraneuronal production of laminin-related molecules in central neurons. We speculate that the laminin-related molecules (neurolaminin) play important roles in trophic or servo mechanisms in the CNS.

Evidence for early blood-brain barrier breakdown in experimental thiamine deficiency in the mouse

In order to assess the involvement of blood-brain barrier (BBB) breakdown in the pathogenesis of thiamine deficiency encephalopathy, autologous albumin immunohistochemistry was performed in mice which were rendered thiamine-deficient by pyrithiamine, a BBB-permeant antagonist of thiamine. In the presymptomatic animals until day 8 of the treatment, histological lesions were not detected by H&E staining. However, localized staining of albumin was evident, suggesting an extravascular leakage of the endogenous intravascular protein. On day 10 of thiamine deficiency, when neurological signs appeared, both histological lesions and massive albumin extravasation were demonstrated in all the animals. The BBB breakdown was only occasionally observed in the brains of mice treated with oxythiamine, a BBB-impermeant antagonist or in control animals. These results suggest that BBB breakdown is not only a phenomenon secondary to tissue destruction, but it is more directly involved in the pathogenesis of thiamine deficiency encephalopathy.

Forebrain ischemia induced by temporary bilateral common carotid occlusion in normotensive rats

Ischemic brain lesions were induced in adult Wistar and Fischer rats by temporary occlusion of the bilateral common carotid artery. The severity of ischemic lesions depended on the duration of carotid occlusion. While 2 h occlusion resulted in 15 deaths among 40 rats and the development of ischemic lesions in 16 of 25 asymptomatic survivors, none died after 0.5 h occlusion and yet 13 of 30 apparently asymptomatic rats had ischemic lesions when examined on day 7. Histological examination combined with immunohistochemistry of autologous albumin for assessing the integrity of the blood-brain barrier (BBB) revealed two distinct lesions: (1) ischemic neural damage with extensive tissue permeation of serum albumin, (2) death of individual neurons sparing other neural elements in the absence of the BBB breakdown. Ischemic neural damage with BBB breakdown was common in animals dying within 48 h after reflow. The lesions without BBB breakdown, on the other hand, were found solely in asymptomatic animals in which groups of severely degenerated neurons were preferentially located in the CA 1 region of the hippocampus, the caudoputamen and deeper layers of the neocortex. The sequential measurements of regional cerebral blood flow (rCBF) in the bilateral hippocampus by the hydrogen clearance method disclosed a steady decrease in rCBF after the occlusion, 51% of the pre-occlusion state at 10 min, 35% at 25 min and 32% at 40 min. The simplicity of procedure could make this model suitable for the study of the pathogenesis of ischemic neuronal damage in a critically low perfusion state.