Typical Central Nervous System Research Articles

A Golgi and ultrastructural analysis of the centromedian nucleus of the cat

The morphology of neurons in the centromedian nucleus (CM) was studied in rapid Golgi preparations of the adult cat. The ultrastructure of the nucleus, particularly its synaptic organization, was also studied with electron microscopy. The CM contains three types of neurons referred to as principal neurons, Golgi type II neurons, and bushy neurons. Principal neurons are the most numerous, have long dendrites, which branch infrequently, and are divided into two subgroups: principal-A neurons with dendrites that arborize radially, whereas principal-B neurons display horizontal orientations. Both subgroups show a frontal orientation in their dendritic organization and give rise to myelinated axons. Golgi type II neurons with their characteristic sinuous dendrites and unmyelinated axons are thought to be interneurons. The occurrence of bushy neurons in the cat's CM is a new finding. These bushy neurons resemble those of thalamic specific relay nuclei and give rise to myelinated axons. In addition to these three cell types, neurons with intermediate features between these three neuronal types are also described. The ultrastructure of CM neurons resembles, in general, typical central nervous system neurons. Presynaptic profiles are classified into four main categories. SR (small round) boutons are small in size, contain clear, round vesicles, and form asymmetrical synaptic contacts with predominantly small-diameter dendrites. LR (large round) boutons are relatively large and contain both clear and dense-cored vesicles. They interdigitate and form multiple, moderately asymmetrical synapses with their postsynaptic targets. Pale profiles are identified by their relatively electron-light appearance. They contain round vesicles and are thought to be dendritic in origin. The last category of presynaptic profiles is pleomorphic boutons. They contain vesicles of different shapes and are further subdivided into two subtypes: pleomorphic-I ends on soma and dendritic trunks, whereas pleomorphic-II contacts small-diameter dendrites. Both subtypes form symmetrical synapses. The glomeruli of specific thalamic relay nuclei generally contain dendrites, LR boutons, and pale profiles. In addition to these, pleomorphic-II boutons also participate in the formation of the glomerulus of the cat's CM.

Incidence and prognosis of central nervous system infections in a birth cohort of 12,000 children.

All types of central nervous system (CNS) infections were investigated in a 1966 birth cohort of 12,000 children from Northern Finland followed up from birth to the age of 14. 174 CNS infections occurred in 167 children, 110 boys and 64 girls. The annual incidence of bacterial CNS infections was 36.3/100,000 and that of viral infections 688.0/100 000. It is concluded that bacterial CNS infections were recorded very fully but only 2/3 of the viral infections could be traced, even though the more severe cases were quite well documented. 8/55 children (14.5%) with bacterial meningitis died; the corresponding figure for viral encephalitis and meningitis (excluding mumps) was 3/67 (4.5%). 17/55 (30.9%) developed mental retardation, epilepsy, cerebral palsy or hearing defect or some combination of these after bacterial CNS infection, and 9 (8.1%) after viral infection. The difference with respect to the children who had not experienced CNS infection was statistically significant only for the bacterial infection cases. CNS infections explained 7.6% of all deaths from 28 days to 14 years, 3% of the handicapping cases of cerebral palsy, mental retardation and epilepsy or some combination of these, and 6.6% of the hearing defects.

Induction of chronic measles encephalitis in C57BL/6 mice.

Chronic measles encephalitis was induced in C57BL/6 mice with the hamster neurotropic strain of measles virus when virus which had been passaged at low dilution in the brains of suckling C57BL/6 mice was inoculated intracerebrally into 1- to 6-month-old mice. One-third to two-thirds of mice surviving the acute infection were consistently found to develop chronic neurologic dysfunction within 3 weeks to 1 year post-infection. The acute mortality was higher in males than in females and showed a slight decline with increasing age in males. Indirect immunofluorescence (IF) studies using measles virus-specific sera from a subacute sclerosing panencephalitis patient and from a hyperimmune rabbit demonstrated abundant viral antigen in regions of telencephalon and diencephalon correlated with the appearance of typical central nervous system signs in both acute and chronic disease. Viral antigen was found in infected neurons in the grey matter. Deposition of immune complexes was minimal as observed in adjacent brain sections stained with goat anti-mouse antibody by direct IF. Occasional necrotic foci and perivascular cuffing were observed in brains from chronically infected mice.

Evaluation of radiation therapy factors in prophylactic central nervous system irradiation for childhood leukemia: A report from the Children's Cancer Study Group

The results of six different types of central nervous system (CNS) prophylaxis were studied in two successive Children's Cancer Study Group clinical trials of children with acute leukemia. Radiation therapy doses and technical factors were analyzed in relation to survival, relapse-free survival, bone marrow and CNS relapse rates, and the toxicities encountered in 656 study children. They were randomized among: (1) 2400 rad to the craniospinal axis (CS) and 1200 rad to the abdomen and gonad (2) 2400 rad CS, (3) 2400 rad to the cranium (Cr) + intrathecal methotrexate (IT/MTX), (4) IT/MTX alone, (5) 1800 rad CS, and (6) 1800 rad Cr + IT/MTX. Hematologic, gastrointestinal and infectious disease complications were highest in group 1. The patients were divided into low and high risk categories, defined as those with initial white blood cell counts below and above 20,000/cumm. for outcome analyses. No statistically significant differences were detected in the five-year rates for relapse-free survival or survival, nor for CNS or bone marrow relapse among the 5 irradiated groups when equipment variables, total doses, field arrangements, fractionation, and protraction were analyzed. These results should be interpreted in the light of the group 4 children who had the highest CNS relapse rates (e.g., 33 % for low risk patients vs. 4–16% for their counterparts in the other 5 groups), but nonetheless had a generally similar bone marrow and survival experience. Exceptions to the foregoing are the better five-year survival rates of 64 and 73 % respectively for group 3 and group 6 high-risk boys, contrasted with 25–42 % for their counterparts in the other 4 groups.

Thermoregulation in Yellowfin Tuna, Thunnus albacares

To determine their capacity for thermoregulation, yellowfin tuna, Thunnus albacares, were subjected to a series of 12-h periods at Ta's of 20, 25, and 30 C. Muscle temperature, measured with an ultrasonic transmitter attached to the fish, and swim speed were simultaneously monitored. No relationship was found between speed and muscle temperature, although metabolic heat production is inexorably linked to the former. Because both direct and inverse muscle temperature/heat production relationships were observed, and because physical (as opposed to physiological) explanations for our data can be discounted, we hypothesize yellowfin tuna are capable of some type of central nervous system (CNS)-mediated physiological thermoregulation.

Progressive demyelination and reparative phenomena in chronic experimental allergic encephalomyelitis.

Chronic experimental allergic encephalomyelitis (EAE), produced in inbred guinea pigs given a single inoculation during the juvenile period with isologous spinal cord in complete Freund's adjuvant, has been studied by light and electron microscopy. Most animals showed a delayed onset of nurologic signs from 12 to 68 weeks post-inoculation (PI), while several were asymptomatic up to 74 weeks PI. Two animals showed a relapsing clinical course. Examination of the spinal cords of all animals revealed chronic demyelination, remyelination, and recent demyelination. Marked perivascular inflammation, including plasma cells, was seen within demyelinated plaques. The usual type of central nervous system (CNS) remyelination was documented but in addition, remyelination of CNS axons by invading Schwann cells was noted. This Schwann cell invasion, not previously seen in EAE, was predominantly in the area of the root entry zone, and occasionally involved extensive areas of the dorsal or ventral horns. The extent of Schwann cell invasion, as well as the usual CNS-type remyelination, demonstrates the reparative capacity of the CNS. The recurrent clinical and morphologic changes in these long-term animals provides further evidence that this model of chronic EAE has many features reminiscent of multiple sclerosis. The underlying immunologic mechanisms responsible for the recurrent disease in these animals are unknown. The presence of plasma cells in the inflammatory exudates might suggest a role for B cells in these chronic animals. The possibility of an intermittent release of loculated adjuvant/antigen accounting for the recurrent disease was considered.

Electron microscopic observations of the nucleus, glial dome, and meninges of the rat acoustic nerve.

AbstractThe rat acoustic nerve is separated into central and peripheral portions by an astrocytic glial dome which is convex peripheralward. The long central portion is of typical central nervous system structure with narrow extracellular space (100–200 Å in width), oligodendrocytes and astrocytes. The glial dome is penetrated by acoustic nerve fibers at a node of Ranvier; the basal lamina of the astrocytes is reflected back over the peripheral Schwann cells at this site. Centrally, the myelin is thinner than peripherally.Acoustic nerve neurons, ranging in size from 25–60 μ, occur in the central portion of the nerve and may be divided into two groups based upon size and density of organelles: large and medium‐sized. All the neurons possess an eccentric nucleus and a peripheral clear zone in the perikaryon beneath which Nissl substance is aggregated, but the medium‐sized neurons have fewer organelles than the large cells. Dendrites and axons are similar in ultrastructure.While collagenous fibrils, fibroblasts, Schwann cells and extensive extracellular space occur in the peripheral portion of the nerve, no structure corresponding to perineurium or epineurium exists. Instead, dura mater surrounds the acoustic nerve within the modiolus and the pia mater encloses bundles of nerve fibers up to the modiolar foramina where it is reflected back as arachnoid mater. Nerve fibers traversing the modiolar foramina are devoid of a meningeal or perineurial covering; this condition also prevails in the osseous spiral lamina, although wisps of pia‐like cells enclose groups of ganglion cells and nerve fibers in the spiral tract. These findings may help to explain acoustic nerve involvement in pathological processes such as meningitis and encephalitis.

Central nervous system damage in the human fetus and newborn infant. Mechanical and hypoxic injury incurred in the fetal-neonatal period.

Four basic types of central nervous system (CNS) damage make their appearance in the fetus and newborn.1-5The lesions are of consistent form and specific origin. Pathologically, the four types of damage stem from the effects of hypoxia and from mechanical trauma incurred during gestation and birth. In each form, the occurrence of the damage is directly influenced by the factor of gestational age. Premature infants are subject to processes of neurological damage which do not occur in the term infant. Recent studies reported by the present investigator have focused attention upon underlying processes of pathogenesis related to mechanical and hypoxic damage to the CNS in the fetus and newborn.1 -5The details of these preliminary studies, first presented for publication in the province of pathology and neuropathology, have generally not come to the attention of the clinician. The present report reviews selected aspects of these investigations for

Effects of Some Drugs on Aggressive Behaviour and the Electrical Activity of the Limbic System

This chapter discusses the effects of some drugs on aggressive behavior and the electrical activity of the limbic system. (+)-3-Methoxy-N-methyl- Δ 6 -morphinan hydrobromide (175-S) is a drug that possesses a taming effect. It is a compound obtained from sinomenine (an alkaloid of Sinomenium acutum) by Sawa and Tsuji. Sinomenine, a histamine-releasing compound, has a weak action on the central nervous system. On the other hand, 175-S has a potent taming effect. To determine the site and mode of action of the drug on the central nervous system, electroencephalographic and behavioral analyses were performed in animal experiments. The results are also compared with those of the typical central nervous system depressants. A part of data on the effect of 175-S on the motor system is also described in the chapter. Pharmacological properties of 175-S are investigated. 175-S has a central nervous system depressant effect. In contrast with chlorpromazine or reserpine, 175-S belongs to another category of neuroleptics.

Studies on the total protein-bound polysaccharide hexose (PBP) of cerebrospinal fluid in the neuropsychiatric field. III. Survey in general paresis, brain tumor and other diseases of central nervous system.

Summary In succession to the former two reports, here has been made the measurement of liquor-PBP on 22 cases of general paresis (15 fresh and 7 chronic cases), 9 cases of brain tumors, 2 cases of meningitis purulenta and 7 cases of other disease types of central nervous system, resulting in the following data. 1 Marked increase of liquor-PEP was observcd in fresh cases of general paresis and brain tumors, the mean values reading 20.8±5.3 mg/L (12–33 mg/L) and 36.0±13.6mg/L (17–55 mg/L), respectively. 2 The liquor-PBP values of 2 cases of meningitis purulenta gave 18 and 57 mg/L, both resulting in marked increase. Rather high values were gained in cases of brain abscess 17 mg/L, multiple sclercsis (16 mg/L) and progressive bulbar palsy (18 mg/L), respectively. 3 The liquor-PBP in chronic cases of general paresis stood at 12.0±1.7 mg/L (9–14mg/L) and that in one case of Sturge-Weber's disease at 12 mg/L, both of which were a little higher than the normal maximal value. while the values in cases of athetosis and Parkinson's disease came within normal limits. 4 On general paresis cases, the variation of liquor-PBP was traced along the course of treatment, proving that the liquor-PEP went decreased in accordance with the grade of amelioration of clinical pictures. The degree of decrease was remarkable in fresh cases. 5 From the above results, considerations were drawn on the prcduction and variation of liquor-PBP and its diagnostic significance.

Treponemal Tests on Cerebrospinal Fluid

Previous studies employing treponemal antigens on spinal fluid have dealt for the most part with the Treponema pallidum immobilization (TPI) procedure of Nelson. Nelson and his co-workers 1 observed positive reactions in all of 33 patients with various types of central nervous system (CNS) syphilis. Interestingly enough, of 25 patients classified as latent syphilis, 6 showed TPI antibody in the spinal fluid. Durel and his co-workers 2 observed only 78% positive TPI reactions in a group of 54 spinal fluids of patients with neurosyphilis. Of 25 patients classified as latent syphilis, 7 were found to have positive TPI tests on the spinal fluid. Zellman and Lutz 3 observed a similar sensitivity of 77% in a group of 26 patients with CNS syphilis. Again, 4 of 11 patients with supposed latent syphilis had positive TPI tests on the spinal fluid. These workers conclude that in neurosyphilis the TPI antibody