Cytoplasmic and axoplasmic density variations in relation to hyperactivity

Summary The density of the cytoplasm and axoplasm of the anterior horn cell in rats was determined by X-ray microradiography. The average density of the cytoplasm of more than 400 cells from control rats was 0.31 g/³, while that of over 600 cells from rats fed IDPN (- iminodipropionitrile) was 0.43 g/³.Hyperactivity developed during the first 5 weeks and was associated with a gradual increase in cytoplasmic density to 0.51 g/³.At 6 weeks there was a drop in density to 0.36 g/³ which coincided with the appearance of axonal balloons having a density of 0.17 g/³.During the 7–12th week on the diet, the cytoplasmic density showed a gradual increase to 0.59 g/³ and the balloons to 0.29 g/³.The volume of the nerve cells remained fairly constant. The density increases were discussed in relation to hypertrophy, dystrophy, and hyperactivity.

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Zusammenfassung Die Dichte des Cytoplasmas und Axoplasmas der Vorderhornzellen von Ratten wurde durch Röntgenmikroradiographie bestimmt. Die mittlere Dichte des Cytoplasmas von mehr als 400 Zellen der Kontrollratten war 0,31 g/³, während die mittlere Dichte von mehr als 600 Zellen der Ratten, die mit IDPN (- iminodipropionitrile) gefüttert waren, 0,43 g/³ war.Hyperaktivität entwickelte sich während der ersten 5 Wochen und war mit einer progressiven Zunahme der Cytoplasmadichte bis auf 0,51 g/³ verbunden.Nach 6 Wochen sank die Dichte auf 0,36 g/³. Diese Tatsache traf mit dem Auftreten der Axonauftreibungen zusammen, die eine Dichte von 0,17 g/³ hatten.Nach 7–12 Wochen zeigte die Cytoplasmadichte eine progressive Zunahme auf 0,59 g/³ und die der Auftreibungen eine Zunahme auf 0,29 g/³.Das Volumen der Nervenzellen blieb ziemlich konstant.Die möglichen Zusammenhänge zwischen Zunahme der Dichte, Hypertrophie, Dystrophie und Hyperaktivität werden dargestellt.

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Supported by U. S. Public Health Grant NB 1305.     

Apurulent bacterial meningitis (compartmental leucopenia in purulent meningitis)

Summary Meningococci and Haemophilus influenzae may invade the subarachnoid space during the bacteriaemic phase without impairment of the blood-CSF barrier and in the absence of any leucocyte reaction. In pneumococcal meningitis the CSF may also contain less than 100 cells/l despite the presence of pure bacterial cultures, but the barrier is completely broken when the serum/CSF concentration ratio is below 10. A clinical analysis of eight patients with fewer than 100 cells/l revealed that the first symptoms of meningitis appeared at least 3 days prior to the diagnostic lumbar puncture. There was a strong neutrophilic reaction in the blood with a prevalence of juvenile forms in most cases, indicating intact antibacterial defence mechanisms. Within 24 h after the start of antibiotic therapy the cell number rose above 2000/l accompanied by disappearance of pneumococci. Six of the eight patients died. In three cases autopsy revealed thick layers of pus over the convexities, indicating a compartmental separation of the ventricles and the spinal subarachnoid space. In one case of late diagnosed bacterial meningitis with a pleocytosis of 430/l the CSF lysozyme level was seven times higher than compatible with this cell number. Hyperphagocytosis and cellular disintegration is thought to cause the leucopenia within the spinal CSF compartment. Apurulent bacterial meningitis can be seen as a disease entity that is a diagnostic pitfall and also a prognostic sign.     

A new mutant strain of syrian hamster with myelin deficiency

Summary A new disorder of central myelination was found in black mutant hamsters showing trembling. The condition was inherited in an autosomal recessive mode. Histologically, a marked myelin deficiency was distributed throughout the central nervous system (CNS), and it was closely related to clinical manifestations observed in the mutants Ultrastructurally, abnormally thin myelin sheaths were observed in all axons with different diameters, and most axons below 1 m in diameter were unmyelinated in the white matter of the spinal cord. There was no overt evidence of demyelination, but some myelin sheaths showed an aberrant configuration. The numbers of glial cells were not reduced, and there were no striking morphological abnormalities in them. It was suggested that there may be a dysfunction of oligodendrocytes resulting in retarded or defective myelination. This trembling hamsters may be a suitable animal model for the study of normal and abnormal myelinogenesis.     

Dysregulation of Reelin and Bcl-2 Proteins in Autistic Cerebellum

Autism is a severe neurodevelopmental disorder with potential genetic and environmental causes. Cerebellar pathology including Purkinje cell atrophy has been demonstrated previously. We hypothesized that cell migration and apoptotic mechanisms may account for observed Purkinje cell abnormalities. Reelin is an important secretory glycoprotein responsible for normal layering of the brain. Bcl-2 is a regulatory protein responsible for control of programmed cell death in the brain. Autistic and normal control cerebellar corteces matched for age, sex, and post-mortem interval (PMI) were prepared for SDS-gel electrophoresis and Western blotting using specific anti-Reelin and anti-Bcl-2 antibodies. Quantification of Reelin bands showed 43%, 44%, and 44% reductions in autistic cerebellum (mean optical density ± SD per 30 g protein 4.05 ± 4.0, 1.98 ± 2.0, 13.88 ± 11.9 for 410 kDa, 330 kDa, and 180 kDa bands, respectively; N = 5) compared with controls (mean optical density ± SD per 30 g protein, 7.1 ± 1.6, 3.5 ± 1.0, 24.7 ± 5.0; N = 8, p < 0.0402 for 180 kDa band). Quantification of Bcl-2 levels showed a 34% to 51% reduction in autistic cerebellum (M ± SD per 75 g protein 0.29 ± 0.08; N = 5) compared with controls (M ± SD per 75 g protein 0.59 ± 0.31; N = 8, p < 0.0451). Measurement of -actin (M ± SD for controls 7.3 ± 2.9; for autistics 6.77 ± 0.66) in the same homogenates did not differ significantly between groups. These results demonstrate for the first time that dysregulation of Reelin and Bcl-2 may be responsible for some of the brain structural and behavioral abnormalities observed in autism.     

Spheroids and altered axons in the spinal gray matter of the normal cat

Summary In our recent ultrastructural studies on synapses of the nucleus dorsalis, central cervical nucleus, and anterior horn of the spinal cord of the normal cat we happened to find spheroids and several types of axonal alterations. These spheroids were up to 39 m in diameter. They were found in myelinated and unmyelinated terminal axons and at the node of Ranvier and showed two different types of internal structure. One type was large and composed of spirally arranged neurofilaments and mitochondria in increased quantity, although the mean population density of mitochondria was not high being 1.4/m² as compared to the normal value 2.0/m². Another type was smaller and consisted of small mitochondria and dense bodies which were increased in number: their mean population densities were 4.5/m² and 1.9/m², respectively.At present, the rare occurrence of spheroids and atypical axonal alterations makes it difficult to determine the origin of affected axons, although some of them presumably arise from primary afferents.     

Die spektralphotometrische Analyse des Liquor cerebrospinalis im UV-Licht

Zusammenfassung Die spektralphotometrische Bestimmung der Absorptionskurve des natürlichen Liquors im UV-Licht gestattet in exakt reproduzierbarer Weise normale und pathologische Liquores zu unterscheiden. Dies ist namentlich bei Verlaufskontrollen von Bedeutung. Ein konstantes Absorptionsmaximum (A) findet sich im kurzwelligen Bereich bis 240 m und ist zur quantitativen Eiweißbestimmung mit einer für die klinischen Bedürfnisse hinreichenden Genauigkeit geeignet. Eine von den quantitativen Eiweißwerten unabhängige Absorptionsbande ( A) hat ihr Maximum bei allen normalen und den meisten pathologischen Liquors bei 266 m Eine Verschiebung nach 275 m kommt vereinzelt bei pathologischen Liquores vor.Eine starke A mit einem Durchlaßgrad von weniger als 30% spricht auch bei im übrigen normalen Liquorwerten für pathologische Veränderungen.Das mittels Perchlorsäure gefällte Liquoreiweiß zeigt in alkalischer Lösung ein dem Grade nach von dem Eiweißgehalt abhängiges Absorptionsmaximum bei 215 m und eine flache Absorptionsbande zwischen 275–285 m.     

Different spinal effects of opioid agonists on spinal and spino-bulbo-spinal reflexes in rats

Summary The effects of morphine-HCl (MOR), methionine-enkephalin (ME) and dynorphin_1–13 (DYN) on spinal and spino-bulbo-spinal (SBS) reflexes were studied. Although spinal intrathecal administration of MOR (15g) did not produce any apparent effect on these reflexes, systemically administered MOR (3mg/kg i.v.) reduced the electrical toe stimulation-induced SBS reflex. Furthermore, MOR (3mg/kg i.v.) increased the polysynaptic reflex induced by electrical stimulation of low-threshold dorsal root afferents in intact (non-spinal) rats, but not in spinal rats. Intrathecally administred DYN (0.5 and 5 g) reduced both the electrical toe stimulation-induced spinal and SBS reflexes, while ME (15g) only reduced the SBS reflex. These results indicate the physiological multiplicity of spinal opioid receptors. MOR may affect supraspinal nuclei but not the spinal pathway which possesses MOR-sensitive opioid receptors, whereas ME and DYN affect spinal opioid peptide receptors and modulate the reflex activities in which they participate.     

Evidence for sequential degeneration of the neurons in the intermediate zone of the spinal cord in amyotrophic lateral sclerosis: a topographic and quantitative investigation

Summary To elucidate the degenerating mechanism of the neurons in the intermediate zone of the spinal cord in classical amyotrophic lateral sclerosis (ALS), the spinal neurons in a patient with ALS, whose muscular strength was fairly well preserved up to death, were examined quantitatively and topographically, and compared with the data of advanced ALS patients and age-matched control subjects reported previously. In advanced ALS patients, anterior horn cells completely disappeared and the medium-sized (nuclear area; 71–150 m²) and large (nuclear area; greater than 151 m²) neurons in the intermediate zone were severely reduced. In the present case, however, the loss of anterior horn cells was severe but the degree was not equal to that of advanced ALS patients, and the neurons in the intermediate zone were quite well preserved. The finding indicates that the primary degeneration may occur in the anterior horn cells and the neurons in the intermediae zone degenerate sequentially in the spinal gray matter in ALS.Supported in part by a Grant-in-Aid for Scientific Research (A) No. 60440046 from the Ministry of Education, Science and Culture, Japan     

Autoradiographic studies of protein turnover in motoneurons of IDPN-treated rats

Summary Autoradiography was performed in order to envisage the turnover of H³-leucin labeled protein in the perikarya of spinal motoneurons and in the axonal balloons formed after repeated administrations of IDPN (--iminodiproprionitrile) in rats.These results suggested that (1) there was no significant, if any,in situ protein synthesis within the axon balloons, (2) the protein turnover was not appreciably altered in the perikarya of the control and IDPN-intoxicated rats, and (3) the labeled protein collected in the axon balloons seemed to be transported from the perikarya to which they were linked with short axonal segments (30 in average length).Supported in part by U.S. NIH Institutional Research Grant (and Neurology Foundation).     

Autometallographic mapping of mercury deposits in the spinal cord of rats treated with inorganic mercury

Summary The autometallographic method has been used in conjunction light and electron microscopy to determine the exact localization of mercury in the rat spinal cord. Adult male Wistar rats were treated intraperitoneally with accumulative doses of mercuric chloride (100–200 g HgCl₂ daily). Transverse sections of the first cervical segment (C₁), fifth cervical segment (C₅), sixth thoracic segment (T₆), and first lumbar segment (L₁) of the spinal cord were examined. The distribution pattern of mercury was dose dependent. In ventral horn motoneurons and neurons of nucleus dorso-medialis (C₁) pronounced staining was found after a total dosage of 1200 g HgCl₂. In nucleus intermedio-lateralis (T₆, L₁) and nucleus cervicalis centralis (C₁) stained neurons were first seen after 2600 g HgCl₂. Ultrastructurally, mercury deposits were exclusively located in lysosomes of neurons, astrocytes, endothelial cells, and ependymal cells.Supported financially by Prof. G. Danscher     

Splanchnic preganglionic neurons in man

Summary The thoracic sympathetic preganglionic outflow is important in the maintenance of postural normotension in man. Normative data on the intermediolateral column (ILC) neuron cell bodies is lacking. Counts and measurements on the right ILC cytons have been performed on the T6, T7 and T8 segments of 12 spinal cords of man obtained within 4–6 h of death. A methodology was employed which has been optimized to prevent shrinkage of cytoplasm from the neuropil and which mathematically corrects the number of cytons of neurons and their frequency distribution for split cell error. The mean cyton counts for T6, T7 and T8 spinal cord segments were 5002, 5004 and 4654 respectively. No significant sex difference was shown. Most cytons ranged in diameter from 8–23 m; the major peak in the size histogram is at 12–13 m and a smaller peak is seen at 16 m. There is a progressive reduction of ILC cytons with age. In adult man approximately 370 cytons (8%) are lost per decade. This reduction in ILC cytons with age may be a morphological basis for postural hypotension of the aged.This investigation was supported in part by NSO 5811, MDA 12, and Upton, Herrick and Schmitter Funds. Dr. Low is in receipt of grants from the Postgraduate Medical Foundation, University of Sydney, and the Royal Australasian College of Physicians     

A morphometric and immunohistochemical study of the vestibular nuclear complex in bovine spongiform encephalopathy

Summary A morphometric and immunohistochemical study of the vestibular nuclear complex was performed on five bovine spongiform encephalopathy (BSE) and five control cow brains. Neurons of the lateral and superior vestibular nuclei were counted at 500-m intervals in 10-m-thick sections, using an image analysis system comprosing a projection microscope and digitising pad linked to a computer. A bimodal distribution of neuron diameters was recognised in the brains of normal cattle. One population of neurons had a mean diameter of 30 m and the other had a mean diameter of 60 m. The vestibular nuclei from BSE cattle had an approximately 50% reduction in total numbers of neurons when compared with controls (P<0.01). Cattle which were clinically diseased longer had the fewest number of neurons preserved. Diminshed numbers of neurons were detected throughout the area studied and affected neurons of all diameters. Immunohistochemical staining for synaptophysin a protein present in synapses throughout the CNS, showed no significant reduction in axon terminals synapsing with vestibular neurons, including vacuolated neurons of BSE brains, when controls and BSE brains were compared. This suggests that de-afferentation of neurons is not the cause of neuronal loss. Prion protein was detected in the neuropil of the vestibular nuclear complex of BSE brains but not control brains. These studies show that previously unsuspected neuronal loss is a significant feature of BSE.     

Selective kainic acid lesions in cultured explants of rat hippocampus

Summary The influence of the excitotoxin kainic acid (KA) on cultivated explants of rat hippocampus was investigated. Addition of 3 M KA to the culture medium over 24–48 h induced a destruction of the pyramidal cells in the CA3 region, whereas the CA1 pyramidal cells and the granule cells were left undamaged. Higher concentrations (10–100 M) of KA destroyed also the latter cell groups. The selectivity of the KA lesion at 3 M was further indicated by the fact that the acetylcholinesterase-positive neurons in the hippocampus were not destroyed through KA administration and that the stereoisomer dihydrokainic acid was ineffective in inducing lesions. Application of tetrodotoxin did not protect the CA3 pyramidal cells from KA lesion, whereas -glutamylaminomethylsulphonic acid (GAMS) only offered a very small, statistically not significant, protection. Baclofen protected the cultures slightly from KA lesions but not when added together with GAMS. Possible mechanisms responsible for the KA lesions in these cultures are discussed.Supported in part by a grant from the Swiss National Foundation for Scientific Research (No. 3.528.-0.83)     

I. c. v. dopamine fails to alter adrenomedullary function in rats

Summary Intracerebroventricularly (i.c.v.) administered dopamine (50–400 g/ kg, 30 min; 400 g/kg, 2 and 4 h) did not induce statistically significant changes in heart adrenaline (presumed to represent the adrenaline release from the adrenals). Only the highest dose (400 g/kg, 30 min) brought about significant increase in adrenal dopamine (reflecting the catecholamine synthesis), accompanied by increase in heart dopamine, indicating leakage of dopamine into the peripheral circulation.The results did not support involvement of the central dopamine receptors in the short-term control of the adrenomedullary function in rats.     

Proliferation of rat intraspinal Schwann cells following tellurium intoxication

Summary A stable population of intraspinal Schwann cells, which developed follwing early postnatal irradiation of the spinal cord, was challenged by the addition of tellurium (Te) to the diet beginning at 30 days of age. Schwann cells incorporating [³H]thymidine were identified by 1 m autoradiographs and by conventional electron microscopy of adjacent thin sections. Autoradiographs of areas with Schwann cell myclination showed extensive labelling of cells in the Te-fed animals. In contrast, control animals which were not fed Te showed little evidence of labelled Schwann cells. These data indicate that Schwann cells in the intraspinal environment show a proliferative response to the presence of Te in the rat's diet, as do Schwann cells in their normal extraspinal milieu.Supported by National Multiple Sclerosis Society grant 1791-A-1, and NIH grant No. NS-23124 to I.D.D. Supported in part by NIH grant 04761, a Jacob Javits Neuroscience Investigator Award to S.A.G.     

Haloperidol increases prolactin release and cyclic AMP formation in vitro: inverse agonism at dopamine D2 receptors?

Summary Haloperidol (30 nM, 3 M) was found to increase prolactin release from GH4C 1 cells transfected with the D 2 receptor cDNA (GH4ZR 7) and from wild-type (untransfected) GH 3 cells, but not from wild-type GH4C 1 cells. In addition, haloperidol (3 M) stimulated cAMP formation in GH 3 cells. It is suggested that haloperidol may act as an inverse agonist rather than as a neutral antagonist at dopaminergic D 2 receptors.     

Prediction of recurrence in meningiomas after surgical treatment

Summary The prognostic significance of nuclear count, nuclear area fraction, and mean nuclear area estimated by automatic image analysis was evaluated in benign meningiomas. One hundred thirty-two meningiomas without recurrences, 39 meningiomas that recurred, and 40 first recurrences were examined. The tumors were classified according to age and eex of patients, localization, and histology; and the correlation between these parameters and the recurrence rate was assessed.The nuclear counts were identical in paraffin sections from meningiomas without recurrences (6.1 nuclei per 1,000 m²) and in meningiomas that recurred (6.4 nuclei per 1,000 m²). The cell count in the recurrences (7.4 nuclei per 1,000 m²) was higher than in the primary tumors. The same relationship was found for the nuclear area fractions, which were identical in primary meningiomas without recurrences and in meningiomas that recurred. The nuclear area fraction was increased in recurrences. The mean nuclear areas were identical in all groups. The histological type was of little significance in prediction of recurrence rate, although bone invasion and necrosis were of some significance. We found a higher recurrence rate in parasagittal meningiomas. Meningiomas that recurred appeared in a younger age group than other meningiomas, and the recurrence rate was higher for males than for females.Supported by grant no. 512-10141 from the Danish Medical Research Council     

Effect of tryptophan metabolites on activity of the epileptogenic focus in the frog hippocampus

Summary In frogs with the epileptogenic foci made by injection of penicilline (1000 U in 0.4 mcl) in the primordial hippocampus it was shown that preliminary administration of two kynurenines quinolinic acid (0,1g) and d,l-kynurenine (1g), in the foci region, and their injection in the functioning epileptogenic foci led to a strong increase of the interictal epileptiform discharges and of the electrographic correlates of fits on the EEG. Anthranilic acid (0.1, 1.0 and S.0g) did not influence the activity of epileptogenic foci. Serotonin (1g) and 5-methoxytryptamine (1g) essentially decreased it. Provocating effect of kynurenines on neurons in epileptogenic foci is supposed to play a certain role in pathogenesis of epilepsy.     

In vitro studies on the possible effects of 1-aminoadamantanes on the serotonergic system in M. Parkinson

Summary Synaptosomes, synaptic vesicles, and membranes were isolated from rat brain homogenates by differential and density gradient centrifugation in sucrose. Synaptosomes incorporated serotonin (5-HT) with two different uptake mechanisms, high affinity: K_t1=47 nM and low affinity: K_t2=660 nM. Both uptake mechanisms are non-competitively inhibited by the potential antiparkinson drugs 1-aminoadamantane (amantadine, D 1: K_i1=57M, K_i2=96M) and 1-amino-3.5-dimethyladamantane (memantine, D 145: K_i1=97M, K_i2=150M). The incorporated 5-HT is released from Synaptosomes on incubation with high concentrations (0.5–5 mM) of the drugs or on electrical stimulation with rectangular pulses of alternating polarity. Subthreshold concentrations of these drugs (5–50M) which are too low to liberate 5-HT increase the electrically stimulated release of 5-HT.—The effect of D 1, D 145, and electrical stimulation on DA release parallels the results observed with 5-HT.The uptake of 5-HT into isolated synaptic vesicles and the binding to isolated nerve ending membranes is non-competitively inhibited by 1-aminoadamantanes. D 145 inhibits the binding of 5-HT to membranes more effectively (K_i=0.95 mM) than its uptake into vesicles (K_i=1.2mM) contrasting with D 1 which is a weaker inhibitor affecting vesicular uptake (K_i=2.5 mM) slightly more than membrane binding (K_i=3.1 mM).The results obtained suggest that, in addition to other mechanisms like receptor stimulation, 1-aminoadamantanes may act in parkinsonian patients by enriching the transmitter content in the synaptic cleft.     

Congenital lead encephalopathy in monkeys

Summary Thirty-one squirrel monkey fetuses were exposed to lead acetate given to the mothers perorally during the last three-fourths or two-thirds of pregnancy. The mean maternal blood lead concentration of the group was 37 g/100 ml and the individual means ranged from 22–82 g/100 ml. Examination of the central nervous system was performed in 15 of the offspring (one abortion, eight stillborns, three neonatal deaths, two killed fetuses and one killed newborn). The mean cerebral weight was reduced for the fetal age (about 10%). Three cerebra were paradoxically overweight for the fetal age as well as for the body weight, probably due to edema. Neurohistology revealed large numbers of characteristic perivascular, petechial hemorrhages in the white matter in six of the fifteen cerebra. In two of these cases, such hemorrhages were also found in the white matter of the cerebellum, brain stem and spinal cord. Examination of four recovered placentas (two after delivery and two at hysterotomies) indicated a lead dose-dependent weight reduction and revealed various pathological lesions. The extensive brain hemorrhages, as well as varying degrees of edema, were seen in still-borns and neonates, while prenatally sacrificed fetuses showed few or no petechial hemorrhages and no signs of edema. It is suggested that lead is involved in the parenchymal growth retardation and the endothelial changes in the prenatal brain, as well as the placental damage, and that prematurity, birth-associated mechanical stress and asphyxia contribute to or precipitate vascular lesions, which may form the basis of acute, or later apparent, neurobehavioral disturbances.