Distribution and progression of amyloid-beta deposits in the amygdala of the aged macaque monkey, and parallels with zinc distribution

In this study, we have mapped amyloid beta (Abeta) deposition in the amygdala of five aged Japanese monkeys (from 23 to 30 years old). In brief, the aged monkey amygdala shows a topographic distribution of Abeta deposits that is subnucleus specific and exhibits a distinct temporal progression. The pattern is similar to the distribution of Abeta deposits in the human amygdala of Alzheimer's patients and of high plaque nondemented cases. The spatial distribution and temporal progression were correlated with the distribution of free zinc (Zn), which is known to mediate Abeta aggregation. For the basolateral group of subnuclei in particular, there is a clear dorsoventral gradient in the progressive distribution of Abeta. Abeta depositions first appear in the ventral division of the lateral nucleus and parvicellular division of the accessory basal nucleus, and then extend into the ventral part of the basal and paralaminar nuclei. All these nuclei are also Zn-dense. Conversely, Zn-weak nuclei, which are more dorsally situated (i.e. dorsal division of lateral nucleus and magnocellular division of basal nucleus) showed only a low level of Abeta deposits, even in brains with the greatest Abeta burden. In contrast to the basolateral group, the central and medial nuclei and cortical group had Abeta deposits only at later stages. In the central and medial nuclei, we identified a lateromedial gradient of Abeta deposits, again similar to the gradient of Zn-distribution. In the cortical group, Abeta deposits are densest in the deep layer, where Zn is also densest. Thus, we suggest the macaque amygdala, with its clear topographic distribution of Abeta deposits, may be an effective model for examining the complex mechanisms of vulnerability to Abeta deposits. A primate model would be advantageous for experimental interventions geared toward therapeutic protection from Alzheimer's disease, including by microarray analysis and genetic manipulation.

Zinc-rich transient vertical modules in the rat retrosplenial cortex during postnatal development

The rat retrosplenial cortex is part of a heavily interconnected limbic circuit, considered to have an important role in spatial memory. Interestingly, the granular retrosplenial cortex has an exceptionally distinct system of dendritic bundles, originating from callosally projecting pyramidal neurons in layer II. These can be detected as early as postnatal day 5; and, although their functional significance remains to be elucidated, the existence of these bundles makes the granular retrosplenial cortex an attractive model system for a wide range of development and functional investigations. Here, we report four results concerning the development of modularity in the granular retrosplenial cortex in rats as investigated by neurochemical markers associated to cortico-cortical and thalamo-cortical connections. Emphasis is placed on zinc, an activity-related substance associated with glutamatergic, non-thalamic terminations. 1) Zinc shows a transient strong expression during early postnatal development, but later than the appearance of the upper layer bundles (at postnatal day 5). By postnatal day 11 to postnatal day 15 staining for zinc achieved its most complex pattern; such that layer I had an elaborate organization both in the tangential and radial dimensions. Three sublaminae were distinguished (layers Ia-c): a superficial, thin tier (Ia) with patchy, moderate staining which periodically intruded into the underlying layer Ib ("funnel" modules), a middle band of variable width and light staining (Ib), and a deep, thin band with heavy and patchy staining (Ic) which, at rostral levels, spread upward into layer Ib (as "dome-like" modules). 2) At postnatal day 15, immunohistochemical methods showed that layers Ia, b zinc-funnels were co-localized with glutamate receptor subunits 2/3, GABA receptor type A alpha1 subunit and the thalamo-cortical marker, vesicular glutamate transporter 2. Layer Ic and the zinc dome-like modules were co-labeled for the cortico-cortical marker, vesicular glutamate transporter 1 and calretinin. 3) The spatial coincidence between zinc funnels in layers Ia, b and vesicular glutamate transporter 2 was further investigated by electron microscopy, which demonstrated co-localization of zinc and vesicular glutamate transporter 2 in synaptic boutons. The unusual co-localization of zinc and thalamo-cortical terminations was confirmed by retrograde transport of zinc to neurones in the anterodorsal thalamic nucleus at postnatal day 9 and postnatal day 13, and can thus be considered a transient zinc expression in thalamo-cortical boutons. This was not observed at postnatal day 28 or later. 4) After postnatal day 18, zinc staining started to fade in all layers. Before postnatal day 21, the heavy staining for zinc in the domes had completely disappeared. Zinc staining in layer Ia and the funnels virtually disappeared after postnatal day 28. A transient expression of zinc is reported in at least one other cortical area (layer IV of barrel cortex from postnatal day 5 to postnatal day 14, maximal at postnatal days 9-11). We conclude that the transient expression of zinc can occur in both limbic and sensory areas, and that down-regulation of zinc in cortical modules might be related to synaptic plasticity and remodeling during development.

ICAM-1 expression on endothelium and systemic cytokine production in cutaneous neutrophilic leukocytoclastic vasculitis in NZBxNZWF1 mice

The present study has examined relationship between cutaneous microvessel injury and adhesion molecule expression on the endothelium by cytokines in NZBxNZWF1 (B/WF1) mice, a model for human systemic lupus erythematosus. In advanced ages associated with overt clinical manifestation, but not in early ages, neutrophils with a minor proportion of monocytes and lymphocytes mainly adhered to the endothelium of capillary and the venule with fragmentation (leukocytoclasis), leading to the vascular injury (leukocytoclastic vasculitis). This was confirmed by the leak of monstral blue from the blood vessel. At this stage LFA-1+ leukocytes adhered to intensely expressed ICAM-1 on the endothelium, and this was paralleled with a significant rise in IL-1 alpha and TNF-alpha in the circulation. The present study suggests that IL-1 alpha and TNF-alpha may, at least in part, be responsible for the increased ICAM-1 expression on endothelium in cutaneous microvessels, resulting in the vascular injury characterized by neutrophilic leukocytoclasis in B/WF1 mice.

A voltage-gated potassium channel, Kv3.1b, is expressed by a subpopulation of large pyramidal neurons in layer 5 of the macaque monkey cortex

In the cerebral cortex, the voltage-gated potassium channel, Kv3.1b, a splicing variant of Kv3.1, has been associated with fast-firing interneurons. Here, we report strong expression of Kv3.1b-protein and mRNA in both Betz and Meynert pyramidal cells of the monkey, as shown by immunohistochemistry and in situ hybridization. Strong expression also occurs in large pyramidal neurons in layer 5 of several cortical areas. In addition, most of these Betz and layer 5 pyramids, and about 10% of the labeled Meynert cells weakly co-expressed the calcium binding protein parvalbumin. Electron microscopy shows that the expression of Kv3.1b is localized to the somal and proximal dendritic cytoplasmic membrane, as expected for a channel protein. These results suggest that some large pyramidal neurons may constitute a functional subpopulation, with a distinctive distribution of voltage-gated potassium channels capable of influencing their repetitive firing properties.

Marked miosis caused by deafferenting the oculomotor nuclear complex in the cat

Animals show highly constricted pupils in certain conditions (e.g., coma). To know the anatomical basis for this miosis, mechanical separation of the oculomotor nuclear complex was done using four transections of the brain. Two frontal transections were placed rostral and caudal to the oculomotor nuclear complex. Two bilateral oblique transections were performed by aiming through the dorsal edge of the Edinger-Westphal nucleus at an angle of 50 degrees from the horizontal plane and vertical to the frontal plane. After the transections, we examined pupillary size for up to 2 weeks to exclude acute effects of deafferentiation. The transections were histologically examined. If the bilateral pupils were highly constricted after the transections, those pupils remained in the miotic state during the survival periods (4-14 days). The deafferented midbrain of the animals, which showed marked miosis, contained the intact oculomotor nuclear complex and nerves with the whole part of the midbrain ventral to them, but with only a small region dorsolateral to them. Given the previous finding that electrical microstimulation of the area ventral to the oculomotor nuclear complex and nerves has failed to elicit pupil constriction, our results suggest that the oculomotor nuclear complex itself could work as a generator for the strong activity of preganglionic pupilloconstrictor neurons.

'In vivo perfusion Turnbull's reaction' for Fe(II) histochemistry in non-anoxic/non-ischemic and anoxic/ischemic cat brains

We developed a simple but ingenious histochemical method, 'in vivo perfusion-Turnbull's reaction', for the visualization of non-heme Fe(II) of the brain; in situ release of Fe(2+) ions was coupled with formation of insoluble reaction product (Turnbull's blue) by in vivo perfusion of acid ferricyanide through the abdominal (non-anoxic/non-ischemic brain) or ascending (anoxic/ischemic brain) aorta in the deeply anesthetized adult cats. Frozen sections of the brain were treated according to the method of Nyguen-Legros et al. [12] to intensify Turnbull's reaction. The method revealed that cytoplasmic Fe(III) was reduced to Fe(II) in oligodendroglias in anoxic/ischemic (for 20 min) brains, and that Fe(II) was concentrated in the neuronal and glial cell nuclei regardless of the presence or absence of blood supply impairment.

Intrastriatal targets of projection fibers from the central lateral nucleus of the rat thalamus

We examined light and electron microscopically intrastriatal targets of projection fibers from the central lateral thalamic nucleus (CL), which is a major relay of cerebello-striatal projections. The study was done in the rat by combining the anterograde tract-tracing with immunohistochemistry for parvalbumin (PV); an anterograde tracer (biotin dextran amine: BDA) was injected into the CL. In the striatum, 91% of BDA-labeled axon terminals made asymmetrical synapses on PV immunonegative dendritic spines (assumed to be those of striatal projection neurons); only 0.5% of BDA-labeled axon terminals made synapses on PV immunopositive dendritic shafts. The remaining BDA-labeled axon terminals were in synaptic contact with PV immunonegative dendritic shafts. The results suggest that the cerebello-striatal projections through the CL predominantly access to striatal projection neurons, with only minor access to PV immunopositive (assumed to be GABAergic) interneurons in the striatum.

A di-synaptic projection from the lateral cerebellar nucleus to the laterodorsal part of the striatum via the central lateral nucleus of the thalamus in the rat

We have examined a cerebello-thalamo-striatal pathway from the lateral cerebellar nucleus (LCN) to the laterodorsal part of the striatum (LDS) through the central lateral nucleus (CL) using light and electron microscopy through the employment of a combination of anterograde and retrograde tracing techniques. Biotinylated dextran amine (BDA) was injected into the unilateral LCN, and used as an anterograde tracer. Cholera toxin B subunit (CTb), used for light microscopy, and wheat germ agglutinin-horseradish peroxidase (WGA-HRP), used for electron microscopy, were injected into the contralateral LDS as retrograde tracers. Light microscopic analysis showed a good overlap of the distribution of BDA-labeled axon terminals and CTb-labeled neurons in the middle third of the CL in both dorsoventral and rostrocaudal axes on the LDS injection side. Electron microscopy confirmed the presence of direct synaptic contacts between BDA-labeled terminals and WGA-HRP-labeled dendrites in the CL.

Electrophysiological characteristics of substantia nigra neurons in organotypic cultures: spontaneous and evoked activities

Morphological and electrophysiological characteristics of dopaminergic and non-dopaminergic neurons in the substantia nigra and their postsynaptic responses to stimulation of the tegmental pedunculopontine nucleus were studied in rat organotypic triple cultures. These cultures consisted of the subthalamic nucleus explant, ventral mesencephalic explant, inclusive of the substantia nigra and the mesopontine tegmentum explant, inclusive of the tegmental pedunculopontine nucleus, prepared from one- to two-day-old rats. Intracellular sharp and whole-cell recordings were obtained from three- to eight-week-old organotypic cultures. Recorded neurons were identified as dopaminergic and non-dopaminergic neurons with tyrosine hydroxylase immunohistochemistry. Dopaminergic neurons had long duration action potentials, prominent afterhyperpolarization, time-dependent inward and outward rectification and strong frequency adaptation. Spontaneous firing patterns varied from regular, irregular to burst firing. Non-dopaminergic neurons had short duration action potentials, in general no rectifying currents, and maintained high firing frequencies. Spontaneous firing patterns in these neurons were irregular or burst firing. Morphological analysis of the recorded neurons labeled with neurobiotin revealed that non-dopaminergic neurons had more extensive arborization of higher-order dendrites than dopaminergic neurons. Dopaminergic and non-dopaminergic neurons receive glutamatergic and cholinergic excitatory inputs from the tegmental pedunculopontine nucleus. These results indicate that morphological and electrophysiological characteristics of substantia nigra neurons in the organotypic culture are generally similar to those reported in in vitro slice and in vivo studies. However, spontaneous activities of dopamine neurons observed in the organotypic culture preparation more closely resemble those in in vivo preparation compared to in vitro preparation.

Morphological study of the tegmental pedunculopontine nucleus, substantia nigra and subthalamic nucleus, and their interconnections in rat organotypic culture

The morphological organization of the tegmental pedunculopontine nucleus, midbrain extrapyramidal area, substantia nigra and subthalamic nucleus and their interrelationships were studied in rat organotypic culture using immunohistochemistry and NADPH-diaphorase histochemistry. Three coronal sections, one containing the tegmental pedunculopontine nucleus/midbrain extrapyramidal area, another with the substantia nigra and the third with the subthalamic nucleus, were obtained from postnatal 1-2-day-old rats. These sections were co-cultured for 3-4 weeks using the roller-tube technique. In the tegmental pedunculopontine nucleus/midbrain extrapyramidal area, the distribution pattern of cholinergic neurons was similar to that found in the in vivo study. We could, therefore, identify the subdivisions of the tegmental pedunculopontine nucleus (i.e., pars compacta and pars dissipata) and the midbrain extrapyramidal area. As in the in vivo situation, glutamate immunoreactive neurons were also located in these areas. Approximately 10% of NADPH-diaphorase positive neurons in the tegmental pedunculopontine nucleus, were glutamate immunoreactive. In the substantia nigra, as in the in vivo, tyrosine hydroxylase immunoreactive (putative dopaminergic) neurons were identified predominantly in the substantia nigra pars compacta, and parvalbumin immunoreactive neurons (putative GABAergic) mainly in the substantia nigra pars reticulata. The subthalamic nucleus was ladened with glutamate immunoreactive neurons. NADPH-diaphorase stained axons originating from the tegmental pedunculopontine nucleus were traced into the substantia nigra and subthalamic nucleus. They were often in close apposition to tyrosine hydroxylase immunoreactive neurons in the substantia nigra. Parvalbumin immunoreactive fibers from the substantia nigra projected heavily to the midbrain extrapyramidal area, but only sparsely to the tegmental pedunculopontine nucleus and the subthalamic nucleus. These findings indicate that the tegmental pedunculopontine nucleus/midbrain extrapyramidal area, substantia nigra and subthalamic nucleus in the organotypic culture have retained a basic morphological organization and connectivity similar to those seen in the in vivo situation. Therefore, this preparation could be a useful model to conduct further studies to investigate functional circuits among the structures represented.

Cornu Ammonis of the dog: a rudimentary CA2 field is only present in a small part of the dorsal division, and is absent in the ventral division of the cornu Ammonis

The relationship between mossy fiber projections and cytoarchitecture was studied in the cornu Ammonis (CA) of three mongrel dogs and two Japanese white rabbits. Precise comparisons were accomplished by examining adjoining sections that were stained by two methods: 1) the Timm-Danscher method which stains for zinc, which is contained in high concentrations in the mossy fiber terminals, and 2) thionin staining of the Nissl substance, so that the mossy fiber projections and cytoarchitecture could be closely compared in each subdivision of the CA. There was a cytoarchitectonically transitional zone (TZ) between CA3 and CA1 in both dogs and rabbits. The TZ was composed of an intermingling of CA3-like large pyramidal cells and CA1-like small pyramidal cells. Across the dorso-ventral length of the rabbit CA, the mossy fiber projections emitted from the dentate granular cell layer extended as far as the distal border of CA3 toward the TZ but did not enter the TZ or CA1. The TZ of the rabbit was equivalent to CA2 of Lorente de Nó (1934), that was characterized by CA3-like large pyramidal cells which did not receive mossy fiber inputs. In the dorsal CA of the dog, the mossy fiber projections extended across the CA3/TZ border, as far as the most distal part of the TZ in one dog but only for a short distance in the other two dogs. That part of the TZ which did not receive mossy fiber projections corresponded with CA2. There were no mossy fiber projections to CA1. In the ventral CA of the dog, however, mossy fiber projections were more extensive than in the dorsal CA, extending across CA3/TZ as well as TZ/CA1 borders to enter the proximal part of CA1. These observations indicate that there is a distinct CA2 in the rabbit CA, and that a rudimentary CA2 is present only in a small part of the dorsal CA of the dog, whereas it is absent in the ventral CA.

Lattice-like collagen fiber meshwork in the iris stroma of the cat: a possible mechanism to generate the tension directed towards the iris root which is required for pupillary dilatation in the sympathectomized eye

NaOH digestion technique for collagen fiber dissection and scanning electron microscopy demonstrated a lattice-like meshwork in the anterior surface of the iris stroma of the cat. The mesh threads were made of collagen fibril bundles. In the constricted pupil, the meshes were square to rhomboid with the diagonals in the direction of the radius or circumference of the iris. In the dilated pupil, however, the meshes were strongly flattened rhomboid or ellipse with a longer diagnoal or axis in the circumferential direction. At the mesh corners facing the pupillary margin or the iris root, the collagen fibril bundles were strongly bent in the iris of the constricted pupil, while they were almost straight or slightly wavy in the iris of the dilated pupil. Accumulation of elasticity tension generated by this small distortion of the iris-mesh threads in the constricted pupil was considered to generate a tension directed towards the iris root, which is required for pupillary dilatation in the sympathectomized eye. On the posterior surface of the iris stroma, numerous thin pleats tightly woven with collagen fibrils traversed straightway through the radial length of the ciliary zone of the iris in both constricted and dilated pupils. The structural changes of these pleats in miosis and mydriasis were very small compared with the meshwork of the anterior aspect of the iris. Therefore, they were considered to work mainly as an iris skeleton.

A di-synaptic projection from the superior colliculus to the head of the caudate nucleus via the centromedian-parafascicular complex in the cat: an anterograde and retrograde labeling study

Centromedian-parafascicular (CM-Pf) complex of the thalamus receives inputs from the superior colliculus (SC). The CM-Pf neurons, in turn, project to the neostriatum. In order to establish a circuitry that the efferent terminals of SC neurons make direct synaptic contacts with thalamostriatal neurons in the CM-Pf complex, the anterograde tracer (biocytin) was injected into the unilateral SC and the retrograde tracer (wheat germ agglutinin conjugated to horseradish peroxidase, WGA-HRP) into the ipsilateral head of the caudate nucleus of the cat. The anterogradely labeled SC fibers and their terminals and retrogradely labeled CM-Pf neuronal elements were examined under light and electron microscope. At the light microscopic level, biocytin-labeled terminal-like varicosities were observed densely in the latero-dorsal part of the CM and the dorsal part of the Pf lateral to the fasciculus retroflexus. These varicosities were often in close proximity to HRP-labeled somata and dendrites of CM-Pf neurons. Electron microscopic analysis revealed that the biocytin-labeled synaptic boutons contained mainly round synaptic vesicles and established asymmetrical synaptic contacts with retrogradely labeled thalamostriatal neuronal elements, including perikarya, and small and large dendrites. In addition, anterogradely labeled terminals made synaptic contacts with unlabeled somata, small and large dendrites, and spines as well as profiles containing synaptic vesicles. These vesicle-containing profiles were considered to be pre-synaptic elements contacting on thalamostriatal neurons or the vesicle-containing dendrites of local circuit neurons. These results demonstrate that the neurons of the CM-Pf complex of the thalamus is involved in a di-synaptic tecto-striatal circuit.

Somatodendritic depolarization-activated potassium currents in rat neostriatal cholinergic interneurons are predominantly of the A type and attributable to coexpression of Kv4.2 and Kv4.1 subunits

Unlike other neostriatal neurons, cholinergic interneurons exhibit spontaneous, low-frequency, repetitive firing. To gain an understanding of the K+ channels regulating this behavior, acutely isolated adult rat cholinergic interneurons were studied using whole-cell voltage-clamp and single-cell reverse transcription-PCR techniques. Cholinergic interneurons were identified by the presence of choline acetyltransferase (ChAT) mRNA. Depolarization-activated potassium currents in cholinergic interneurons were dominated by a rapidly inactivating, K+-selective A current that became active at subthreshold potentials. Depolarizing prepulses inactivated this component of the current, leaving a delayed, rectifier-like current. Micromolar concentrations of Cd2+ dramatically shifted the voltage dependence of the A current without significantly affecting the delayed rectifier. The A-channel antagonist 4-aminopyridine (4-AP) produced a voltage-dependent block (IC50, approximately 1 mM) with a prominent crossover at millimolar concentrations. On the other hand, TEA preferentially blocked the sustained current component at concentrations <10 mM. Single-cell mRNA profiling of subunits known to give rise to rapidly inactivating K+ currents revealed the coexpression of Kv4.1, Kv4.2, and Kv1.4 mRNAs but low or undetectable levels of Kv4.3 and Kv3.4 mRNAs. Kv1.1, beta1, and beta2 subunit mRNAs, but not beta3, were also commonly detected. The inactivation recovery kinetics of the A-type current were found to match those of Kv4.2 and 4.1 channels and not those of Kv1.4 or Kv1. 1 and beta1 channels. Immunocytochemical analysis confirmed the presence of Kv4.2 but not Kv1.4 subunits in the somatodendritic membrane of ChAT-immunoreactive neurons. These results argue that the depolarization-activated somatodendritic K+ currents in cholinergic interneurons are dominated by Kv4.2- and Kv4. 1-containing channels. The properties of these channels are consistent with their playing a prominent role in governing the slow, repetitive discharge of interneurons seen in vivo.

Cornu ammonis of the cat: lack of a separate field of CA2

Close comparison of Timm or Nissl stained adjoining sections of the cat cornu Ammonis (CA) disclosed the lack of a separate CA2 field, which was defined as a field of CA characterized by giant pyramids similar to those of CA3 and by absence of mossy fiber inputs in mice, rats, monkeys and humans. In the cat CA, mossy fiber terminals stained by Timm's method filled the hilar region (CA4) of the dentate gyrus and extended through the stratum pyramidale and/or stratum lucidum of the giant pyramidal part of CA as far as the border with CA1, which was clearly delineated by sudden appearance of smaller pyramids. Thus, there was no separate giant pyramidal field devoid of mossy fiber inputs in the cat CA. Unlike other mammals, some parts of CA1 also received mossy fiber projections in the cat.

Anisocoria--a pupillary sign of hippocampal lesions: an experimental study in the cat by using neurotoxins

Pupillary inequality developed after unilateral lesions of the hippocampal formation (HF) of the cat. Lesions were made by an injection of a small amount of colchicine, ibotenic acid or kainic acid. In all anisoric cats, the pupil on the side of the lesions was invariably smaller than its partner. Evident pupillary inequality developed in the cats with dorsal HF lesions. Although there was a considerable variation in the extent and the location of lesions among these cats, the involvement of the giganto-pyramidal CA 3-2 appeared very responsible for the development of the pupillary sign. However, an evidently anisoric cat hat a lesion affecting only the prosubiculum and the subiculum in the posterior part of the dorsal HF. Despite a large involvement of CA 3-2 with or without coincident injuries to CA1, the prosubiculum and the subiculum, only slight pupillary inequality developed following ventral HF lesions. Evident anisocoria in the cats with large dorsal HF lesions disappeared after bilateral cervical sympathectomy, implying that the asymmetry of sympathetic nervous activity might be critically involved in the development of the pupillary sign. The hippocampo-spinal pathway relayed by the lateral septal nucleus and, then, by the lateral hypothalamic area to terminate in the intermedio-lateral cell column of the spinal cord was considered to be most concerned with anisocoria caused by HF lesions.

Quantitative electromicroscope study of the oculomotor parasympathetic neurons projecting to the ciliary ganglion in cats: comparison of the synaptic (axon-somatic and axo-proximal dendritic) organization of anterior-dorsal and ventral cell groups

The synaptic organization of the oculomotor parasympathetic preganglionic neurons (OPNs), labeled retrogradely after a horseradish peroxidase (HRP) injection into the ciliary ganglion, was studied in cats by electron microscopy. We divided the OPNs into two groups, anterior-dorsal (ADG) and ventral (VG) cell groups, based upon physiological studies in cats suggesting that accomodation-related OPNs are predominantly located anterior and dorsal to the somatic nuclei of the oculomotor nuclear complex (i.e., the anteromedian and Edinger-Westphal nuclei, and the ventral central gray area), while pupillo-constriction-related OPNs are predominantly located ventral to the somatic nuclei (i.e., the ventral tegmental area). The synaptic organization of these two groups was quantitatively compared, using a nested analysis of variance to determine statistical significance (P < 0.05). Partial reconstructions of the labeled somata and proximal dendrites were made from tracings of electron micrographs of every 2nd section in serial ultrathin sections that included the nucleolus or were adjacent to sections that included the nucleolus. The mean number of boutons of apposition on a reconstructed labeled soma of VG was significantly greater than that of ADG (mean +/- SD; ADG, 5.3 +/- 3.3; VG, 8.6 +/- 3.2). The mean synaptic density on a VG soma was significantly greater than on an ADG soma (mean +/- SD; ADG, 3.74 +/- 2.11 counts/100 microns2; VG, 6.30 +/- 1.99 counts/100 microns2). The mean synaptic covering ratio on a VG soma was significantly greater than on an ADG soma (mean +/- SD; ADG, 5.21 +/- 2.91%; VG, 10.14 +/- 3.76%). The mean estimated number of boutons of apposition on a VG soma was significantly greater than on an ADG soma (mean +/- SD: ADG, 53 +/- 36; VG, 100 +/- 48). Boutons were classified on the basis of the shape of their synaptic vesicles as S-type (containing spherical clear synaptic vesicles) or P-type (containing both flattened and spherical clear synaptic vesicles). The significantly greater than on an ADG soma (mean +/- SD; ADG, 0.31 +/- 0.20; VG, 0.67 +/- 0.18). The differences demonstrated in this study reinforce, morphologically, the assumption of functional localization of OPNs, and further allow us to estimate the relative characteristics of the synaptic organization of accommodation-related OPNs and pupillo-constriction-related OPNs.

[Usefulness of endotoxin-specific limulus test for the measurement of endotoxin in cerebrospinal fluid in diagnosis of bacterial meningitis]

Using a new endotoxin-specific chromogneic limulus assay (Endoscopy test), endotoxin concentrations were measured in 93 specimens of cerebrospinal fluid (CSF) from 66 pediatric patients. Eighteen patients were diagnosed as having menigitios. Of these, 6 cases (group A) with gram-negative meningitis proven by culture had high CSF endotoxin concentrations of 115.3, (82-133) (median, range) pg/ml. Ten cases (group B) with gram-positive or aseptic meningitis had endotoxin concentrations of 2.15 (0.1-3.6) pg ml. Other 2 cases with bacterial meningitis (group C), in whom no pathogen was detected, had CSF endotoxin concentrations of more than 100 pg/ml. Four cases with encephalitis (group D) and 45 cases with non-meningitis or non- encephalitis (group E), had CSF endotoxin concentrations of less than 5 pg/ml. Despite a negative culture after antibiotic treatment in group A patients, endotoxin was cleared slowly from the CSF. A clearing of endotoxin from CSF was followed by alleviation of fever with a more gradual decline in CRP values. In 2 cases of group C, the negative bacterial culture appeared to be attributable to the previous treatment with antibiotics. However, these patients had high CSF endotoxin levels, indicating gram negative bacterial meningitis. In 17 CSF specimens from 5 patients of group A, in whom Haemophilus influenzae was detected on admission, an additional a latex agglutination test for the detection of H. influenzae polysaccharide antigen was performed. Only 3 specimens from 3 patients with CSF endotoxin concentrations of more than 80 pg/ml had a positive agglutination test. These results suggest that quantitation of endotoxin concentrations is useful for the diagnosis of gram-negative meningitis. And also, the clearance of endotoxin from CSF during treatment appears to be useful in determining the timing of when antibiotic should be stopped.