Biomedical subjects

L J Garey

Publications and source records attributed to L J Garey.

At least 19 recordsLinked to original sources

PubMed1995

Spatial periodicity of NADPH-diaphorase and synaptophysin, but not SNAP-25, reactivity in the monkey cerebellar cortex.

We recently described a parasagittal patchy organisation of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in the granular layer of the rat cerebellum. We now report the pattern of NADPH-d distribution in the primate cerebellum and its relationship to two synaptic proteins, synaptophysin and synaptosomal associated protein 25 kDa (SNAP-25), using histochemistry and immunocytochemistry. NADPH-d reactivity was localised in the molecular and granular layers (ML, GL) and a subset of infraganglionic plexuses (IGPs), but not in the Purkinje cell layer and the white matter. In ML, the histochemical reactivity was dense and relatively homogeneous in the neuropil, and moderate in the stellate cells. A patchy organisation of NADPH-d in GL was detected in both horizontal and parasagittal sections. In the IGPs staining for NADPH-d revealed modular positive zones alternating with negative ones. The positive and negative IGP zones were usually congruent with the high and low NADPH-d reactivity in GL, respectively. Both synaptic proteins were strongly expressed in the neuropil in ML and GL, and their patterns were relatively homogeneous. However, synaptophysin was present in a subpopulation of IGPs organised in modules which corresponded to those expressing NADPH-d. Our results indicate that the NADPH-d modular system is more complicated in the primate cerebellum than in the rat. In addition, we have provided suggestive evidence of a co-expression of NADPH-d and synaptophysin in selected IGP modules in primate cerebellum, which suggests that nitric oxide may be involved in the activity of the Purkinje cells by affecting the basket cell synaptic input.

Animals↗

PubMed1995

Localization of glial fibrillary acidic protein and glutamine synthetase in the human cerebral cortex and subcortical white matter--a double immunolabelling and electron microscopic study.

Astrocytes in the human cerebral cortex and subcortical white matter were labelled using antibodies to glial fibrillary acidic protein, or double labelled for glial fibrillary acidic protein and glutamine synthetase, and studied by light and electron microscopy. We described two types of astrocytic processes in an earlier study of human cortex: glial-filament-rich but mitochondria-poor, and filament-poor but mitochondria-rich. The question arose as to whether these were different segments of the same process, or whether the filament-rich processes belonged to a subpopulation of 'fibrous' astrocytes. In the present study no such fibrous astrocytes were found in histologically normal cortex, and all glial fibrillary acidic protein positive cell bodies in the cortex were also glutamine synthetase-positive, and had features of protoplasmic astrocytes. Since the processes of fibrous astrocytes in the white matter seldom extended more than 40-50 microns beyond the cell bodies, they were unlikely to account for the filament-rich astrocytic processes that were observed in the cortex by electron microscopy. The filament-rich but mitochondria-poor, and the filament-poor but mitochondria-rich processes are seen in continuity in the cortex and must therefore both stem from cell bodies with features of protoplasmic astrocytes.

Adolescent↗

PubMed1994

Bcl-2 proto-oncogene protein immunoreactivity in normally developing and axotomised rat retinas.

This study demonstrates immunocytochemically that bcl-2 (B cell lymphoma) proto-oncogene protein is expressed by two populations of retinal cells, one in the inner retina representing developing neurons or glia at perinatal stages, and the other identified as Müller cells from postnatal day 10 onward. An increase in bcl-2 immunoreactivity was detected in the Müller cell processes after neonatal optic tract lesion or optic nerve transection in adult rats. These results suggest that bcl-2 protein may function on cellular differentiation, maturation and homeostasis in the inner retina, and its expression by Müller cells can be up-regulated by the degeneration of ganglion cells.

Animals↗

PubMed1994

Development of NADPH-diaphorase activity in the rat neocortex.

The activity of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), an enzyme related to the synthesis of nitric oxide (NO), was studied histochemically in rat neocortex from the day of birth (P0) to young adulthood. At birth, NADPH-d containing neurons were already identifiable, sparsely distributed in the deep half of the pallium of the cerebrum. In addition, weakly stained bands of NADPH-d positive neuropil were detectable in layers VI and deep V and the cortical plate (CP). During the first postnatal week, NADPH-d positive neurons increased markedly, especially in CP and the superficial layers. By P7 the cells were mainly in layers VIb and II/III. Differential NADPH-d activity in the neuropil during this period appeared as higher activity gradually moving upwards until the highest intensity localised in layers II and upper III. In the caudal part of the cortex, the higher activity covered the whole of the supragranular layers. By the end of the second postnatal week, both the number and laminar distribution of NADPH-d neurons were adult-like, still mainly in layers VIb and II/III. The staining intensity in the neuropil was generally reduced but the banding pattern seen at P7 was still present. No detectable changes in the patterns of NADPH-d positive cells and neuropil in the neocortex occurred after the second postnatal week. The rostral part of the cortex matured slightly earlier than the caudal part. These results show that the development of NADPH-d activity correlates with the laminar differentiation and suggest that NADPH-d or NO may play an important role in the maturation of cortical neurons including the establishment of functional connections.

Animals↗

PubMed1994

Protein gene product 9.5-immunoreactive retinal neurons in normal developing rats and rats with optic nerve or tract lesion.

The present immunocytochemical study indicates that protein gene product 9.5 (PGP 9.5) in the rat retina first appears in a population of neurons in the inner and central part of the neuroblast layer at embryonic day (E) 14. Presumptive horizontal cells which are PGP 9.5 positive were observed at E17. At birth, cells in the inner nuclear layer and ganglion cell layer (GCL) as well as the inner plexiform layer (IPL) were positive. Further differentiation, particularly the appearance and the formation of immunoreactive sublaminae in the IPL, was observed in the first 2 postnatal weeks. This pattern reached adult levels by postnatal day 14. In rats with unilateral neonatal optic tract lesion or optic nerve transection as young adults, 43-45% of the immunoreactive cells were lost in the GCL. However, only minor changes were detected in the IPL, suggesting that amacrine cells contribute mainly to the PGP 9.5 immunoreactivity in this laminar zone of the retina.

Aging↗

PubMed1994

Distribution of preprosomatostatin mRNA in the rat parietal and temporal cortex.

The cerebral cortex of normal adult rats was studied by in situ hybridisation histochemistry, using digoxigenin-labelled oligonucleotide probes to preprosomatostatin (SOM). Labelled neurons were present in all cortical layers except layer I. They varied in staining intensity from light to heavy. There was no correlation between the size of the soma and staining intensity. A variety of neuronal types were SOM-positive. Some were clearly non-pyramidal, with a rounded soma and horizontal or oblique stem dendrites, while others had a prominent ascending apical dendrite and were interpreted as pyramidal neurons.

Animals↗

PubMed1993

Parasagittal patches in the granular layer of the developing and adult rat cerebellum as demonstrated by NADPH-diaphorase histochemistry.

The development of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in the rat cerebellum was studied histochemically. NADPH-d reactivity was observed in the internal granular layer and some Purkinje cells by the end of first postnatal week (PW1). By PW2, the staining was localized in the granular layer (GL) and the molecular layer (ML), but not in the Purkinje cell layer. The staining in GL and ML increased further, and parasagittally organized NADPH-d patches in GL were recognizable by PW3. These patches were more distinct and almost adult-like by PW4. These results provide the first evidence of a patchy organization of NADPH-d activity in GL and suggest that NADPH-d plays an important role in the maturation and function of the cerebellum.

Amino Acid Oxidoreductases↗

PubMed1993

Distribution of glial fibrillary acidic protein and glutamine synthetase in human cerebral cortical astrocytes--a light and electron microscopic study.

Human cerebral cortex was studied immunocytochemically by light and electron microscopy using antibodies against glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS). Glial fibrillary acidic protein-positive cells and processes were present in both cortex and white matter, but in contrast glutamine synthetase-positive cells and processes were present only in cortex. Cell bodies which contained glutamine synthetase had typical ultrastructural features of protoplasmic astrocytes. Glutamine synthetase-positive processes were often present near asymmetrical synapses in the neuropil. These processes often contained mitochondria, but not glial filaments, and were different from unlabelled astrocytic processes, which seldom contained mitochondria, but had large numbers of glial filaments. Glutamine synthetase immunoreactivity therefore affords a means of distinguishing between these two types of astrocytic processes in the human cerebral cortex.

Adult↗

PubMed1993

Ultrastructural features of biopsied temporopolar cortex (area 38) in a case of schizophrenia.

An electron microscopic study of tissue from area 38 of the temporopolar cortex obtained at surgery from a schizophrenic patient has established that, although the ultrastructure of this area was in general similar to that found in normal human cerebral cortex, the neuropil contained many unusual asymmetrical synapses. Their synaptic vesicles were clumped, often away from the synaptic thickenings, and the thickenings themselves were short, compared to the total length of apposed pre- and postsynaptic membranes. Some preterminals were unusual in that they were myelinated. The affected terminals were always of the asymmetrical variety, and therefore probably excitatory. Glutamate is likely to be the transmitter at, at least, some of these synapses. The clumped, but numerous, synaptic vesicles, together with short synaptic active zones, is consistent with previous observations of normal glutamate levels in schizophrenic brain, but reduced numbers of glutamate receptors in some cortical areas.

Aged↗

PubMed1993

Injury-resistant retinal ganglion cells that are rich in cytochrome oxidase.

Previous studies have demonstrated that the vast majority of retinal ganglion cells (RGCs) die one month after optic nerve transection. However, a small percentage do not degenerate. The present study examined one aspect of the chemical nature of these surviving RGCs using cytochrome oxidase (CO) as a neuronal marker in whole-mounted retinae. In the normal retina, 4.3% of the total population of RGCs show high CO activity. One month after optic nerve transection, 37% of the CO-positive RGCs counted in the control retinae survive and, because they stain with CO, must be metabolically active. Previous studies have shown that only up to 10% of the total RGC population survive optic nerve transection. The implication of our results is that the CO-positive RGCs, as a subpopulation, are more resistant to injury than the general population of RGCs.

Animals↗

PubMed1993

Neuronal morphology in the lateral geniculate nucleus of the porpoise (Phocoena phocoena).

The Golgi and Nissl methods and cytochrome oxidase (CO) histochemistry were used to study the overall structure and neuronal morphology of the lateral geniculate nucleus (LGN) of the Black Sea porpoise (Phocoena phocoena). Differences were observed between dorsal and ventral portions of the nucleus in terms of cell size and CO staining. In addition to prominent fibre bundles crossing the LGN horizontally, vertically oriented variations of CO staining were apparent. Neuronal types in the LGN corresponded broadly to those observed in land mammals. The commonest were variants of multipolar cells, and may represent thalamocortical relay cells. Various other types were probably interneuronal.

Animals↗

PubMed1992

Prenatal development of GABA-immunoreactive neurons in the human striate cortex.

The prenatal development of neurons immunoreactive to gamma-aminobutyric acid (GABA) in the striate cortex (area 17) of human foetuses aged from 14 weeks to term was studied immunocytochemically. In the 14 week foetus GABA-immunoreactive cells occurred in all layers of area 17 with the highest density in the marginal zone (MZ), subplate (SP), deep intermediate zone (IZ) and ventricular zone (VZ). The cortical plate (CP), which gives rise to most of the definitive adult cortical layers, had relatively low concentrations of GABAergic cells. By 17 weeks the density in the proliferative VZ had declined. At 20 weeks some of the adult layers were recognisable; the density of GABA-positive neurons was now highest in the definitive cortex, especially the deep layers (layers VI and V), was lower in the superficial cortical plate, and was lowest in IZ, where the white matter would form. The peak of GABA-immunoreactive neuronal density continued to move superficially during development, and was in layer IVc by 30 weeks. The laminar distribution stabilised from 30 weeks with three dense bands: in layer IVc and superficial V, layer IVa, and layers II and superficial III. The tangential distribution of GABAergic neurons was determined in two older brains (32 and 39 weeks) and no unequivocal spatial periodicity was observed in this plane. The mean cross-sectional area of GABAergic neurons in area 17 increased with foetal age, and also increased from superficial to deep layers at each age. Most GABA-immunoreactive neurons in younger brains contained immunonegative or weakly positive nuclei and had few visible processes, while in the older brains most neurons contained positive nuclei and had more visible processes. The proportion of GABA-immunoreactive bipolar cells declined during development while that of multipolar cells increased. GABAergic neurons thus differentiate early in human foetal striate cortex. They are initially most numerous in the proliferative layers deep to the developing definitive cortex; from 20 weeks of gestation, their peak moves superficially into the maturing deep layers (VI and V) and a stable laminar distribution is attained by 30 weeks, with peaks in layers II/IIIm, IVa and IVc/V. There is no obvious horizontal periodic distribution before term.

Axons↗

PubMed1992

Development of parvalbumin immunoreactive neurons in normal and intracranially transplanted retinas in the rat.

Retinas from embryonic day 14 Sprague-Dawley rats were transplanted to the midbrain or cerebral cortex of newborn (P0) rats of which the right eye was enucleated at the time of transplantation. Parvalbumin immunoreactive (PV-I) neurons were studied in the developing retinal transplants, and in the remaining retina of the host, as well as in normal retinas. PV-I neurons were identifiable in retinas of normal and host rats from postnatal day 5 (P5) onward, with the PV-I somata primarily in the inner half of the inner nuclear layer and in the ganglion cell layer. An adult-like distribution of PV-I neurons was attained at P35, as judged by cell packing density, intensity of immunostaining, laminar distribution and soma size of subpopulations of PV-I cells. A similar time course of development and distribution of PV-I somata was observed in the retinal transplants, except for some minor differences such as a slight delay in PV-I cells achieving their final distribution. These findings provide evidence that PV-I neurons can survive, differentiate and mature according to predetermined programmes intrinsic to the retinal tissue following transplantation to a new and foreign environment.

Animals↗

PubMed1991

Distribution of GABA and neuropeptides in the human cerebral cortex. A light and electron microscopic study.

Antibodies were used to identify neurons in human frontal and temporal cortex that were immuno-positive to gamma-aminobutyric acid (GABA) and the neuropeptides vasoactive intestinal polypeptide (VIP), substance P (SP) and somatostatin (SOM). Specimens were taken at surgical biopsy and fixed immediately after removal. The results described for both light and electron microscopy were obtained when relatively high concentrations of glutaraldehyde (2.5-3%) were present in the fixative. Specimens were examined from three adults and an infant aged 5 months. GABAergic neurons were present in all cortical layers, with fewest in layers I, deep III and V, and were mainly small, and round or oval. No labelled pyramidal neurons were detected. GABAergic puncta were common in the neuropil, probably representing axonal profiles. VIP-neurons were also found in all layers, including layer I, and were approximately twice as numerous as GABA-cells. SP-positive cells were found throughout the layers, but were sparse in layers I and VI. They were about three times commoner than GABAergic neurons. SOM-reactivity was demonstrated in about the same number of cells as that for SP. Again, this involved all layers, but layer I least. Peptidergic neurons were larger, on the average, than GABAergic cells, and were frequently pyramidal in character. In the infant, the distribution, size and frequency of immunoreactive neurons were similar to those in the adult. However, GABAergic puncta were commoner.

Cerebral Cortex↗

PubMed1991

Laminar distribution of cytochrome oxidase staining in cetacean isocortex.

The distribution of cytochrome oxidase activity was studied in the cerebral cortex of two species of cetaceans, the harbour porpoise Phocoena phocoena, and the bottlenose dolphin Tursiops truncatus. Two main patterns of distribution of cytochrome oxidase were detected. The first, characteristic of the visual and auditory cortices of the lateral and suprasylvian gyri, is typified by a peak density in layer III, contrasting with low levels in layers II, V and VI. The second is found in wide areas of the limbic lobe, the insular cortex, the temporal operculum and the occipital cortex. In these regions, distribution of cytochrome oxidase is more uniform, with little difference between layers III, V and VI. A transitional pattern is found in the most dorsal parts of the limbic lobe, the parietal operculum, the ectosylvian gyrus and in orbitofrontal cortex. As areas of high cytochrome oxidase activity have been described in various land mammals to correspond to zones of major excitatory input and, in particular, to characterise the cortical layers that receive thalamocortical afferents, we propose that the thalamocortical input to cetacean sensory cortex, in which a typical layer IV is absent, may be mainly to layer III. This view is supported by the high density of neurons positive for the inhibitory transmitter gamma-aminobutyric acid that is also found in layer III of cetacean cortex, another typical feature of thalamocortical recipient zones.

Animals↗

PubMed1991

Ultrastructural characteristics of human adult and infant cerebral cortical neurons.

Biopsy specimens of human cerebral cortex from three adults and two infants were studied by correlating their light microscopic features in semithin sections with their ultrastructural characteristics. There was good tissue preservation, due to a minimum delay between obtaining the specimens and fixation. Pyramidal cells had a prominent apical dendrite, fine heterochromatin clumps in the nucleus and generally small numbers of cytoplasmic organelles, except for numerous free ribosomes in some of the large pyramids of Layers III to VI. Non-pyramidal cells lacked an apical dendrite and were further classified, on size and ultrastructure, into small, medium and large types. Large numbers of asymmetrical and symmetrical synapses were present in the neuropil but very few axosomatic synapses were found in the human cerebral cortex compared with subhuman primates and other mammals. Some symmetrical synapses were characterised by the presence of wide pre- and postsynaptic densities. The same general features of the adult cortex were also encountered in the infant, with certain exceptions. Many of the infant neurons had less densely packed heterochromatin, but greater numbers of free ribosomes, compared with the adult, and lipofuscin was absent. There was a total absence of myelinated fibres from the infant cortex; more large diameter dendrites were present than in the adult and axosomatic synapses were commoner.

Biopsy↗

PubMed1990

Pyramidal neurons are immunopositive for peptides, but not GABA, in the temporal cortex of the macaque monkey (Macaca fascicularis).

Areas 20, 21 and 22 of the temporal neocortex of the macaque monkey (Macaca fascicularis) were studied with immunocytochemical and electron-microscopic techniques to localise neurons immunoreactive to the neuropeptides vasoactive intestinal polypeptide, substance P and somatostatin, and to gamma-aminobutyric acid (GABA). GABAergic neurons were found in all cortical layers, but especially in layers II, IV and VI. They were all of non-pyramidal morphology, comprising small round cells, and bipolar or multipolar forms. Presumed GABAergic axon terminals were also common. Peptidergic neurons were also found in all layers, but they consisted of cells of many morphological types, including pyramidal cells. Compared with previous descriptions in other cortical areas and in other animals, we find a greater proportion of peptidergic temporal cortical neurons compared to the GABAergic population. The immunopositive neurons were easily recognisable ultrastructurally from non-reactive neurons by the dense labelling of the cytoplasm and nucleus. Immunopositive and negative neuronal somata were often contiguous, providing evidence for the specificity of the immune reaction. Stem dendrites were often labelled for a short distance from the soma, and other strongly reacting dendritic segments were found in the neuropil, as were labelled axons. Neurons labelled for GABA had features typical of non-pyramidal cells, but neuropeptides were also found in cells with pyramidal characteristics.

Animals↗

PubMed1990

Neuronal architecture of the human temporal cortex.

The cortex of the superior, middle and inferior temporal gyri of the human cerebral hemispheres was investigated using Nissl, Golgi and fibre staining techniques. Brodmann's (1909) area 41, corresponding to the primary auditory cortex in Heschl's transverse temporal gyri, consisted of typical koniocortex, and formed the middle part of the superior temporal plane (the buried lower bank of the Sylvian fissure). Anteriorly the superior temporal plane contained area 22, and posteriorly the planum temporale (part of area 42). The lateral surfaces of the superior, middle and inferior temporal gyri respectively correspond to areas 22, 21 and 20. Neurons in much of the left temporal cortex, apart from area 41, formed radial columns. This columnar organisation was most pronounced posteriorly and superiorly, so that anterior area 20 was the least columnar and area 42 the most. The right temporal cortex was markedly less columnar than the left. Golgi studies showed a variety of pyramidal and non-pyramidal neurons, with specific varieties typical of individual cortical layers.

Adult↗