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↗

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↗

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↗

PubMed1990

The thalamic projection to the sensory neocortex of the porpoise, Phocoena phocoena.

Retrograde tracers were injected in various parts of the neocortex of the porpoise (Phocoena phocoena). Labelled thalamic neurons were plotted in three-dimensional reconstructions. The lateral geniculate nucleus projects to the visually excitable part of the lateral gyrus. Ventral parts of the medial geniculate nucleus project to the auditory area of the suprasylvian gyrus, while dorsal medial geniculate projects to the 'secondary' auditory area of the ectosylvian gyrus and to the temporal operculum. The ventrobasal and ventropostero-inferior complex projects to cortex anterior to the suprasylvian auditory area, corresponding to somatosensory function. The main projection of the inferior pulvinar is to the suprasylvian gyrus, that of the medial pulvinar to the ectosylvian gyrus, and of the lateral pulvinar to the border of the lateral and suprasylvian gyri. The lateral and posterior complexes project to perisylvian cortex. Throughout the thalamus there is a rough topographic organisation. Lateral to medial through the thalamus represents progression from medial to lateral over the cortex from lateral gyrus to perisylvian cortex. Anterior in cortex is represented by anteroventral in thalamus, and posterior in cortex by posterodorsal in thalamus.

Animals↗

PubMed1989

Quantitative distribution of GABA-immunoreactive neurons in cetacean visual cortex is similar to that in land mammals.

Sections of the anterior portion of the visual cortex in the lateral gyrus of the Black Sea porpoise were studied to determine the neuronal architecture and numerical density, and the distribution of neurons immunoreactive to gamma-aminobutyric acid (GABA). Cytoarchitecture and neuronal density are similar to those described in another cetacean, the bottlenose dolphin. GABA-positive neurons are distributed through all layers of the visual cortex but are especially dense in layers II and III, and comprise some 20% of the total neuronal population in this part of the cortex. The distribution of GABA-positive neurons is similar to that found in land mammals.

Animals↗

PubMed1989

Comparison of neuronal and glial numerical density in primary and secondary visual cortex of man.

The numerical density of neurons and glial cells was estimated in visual area 18 of the adult human cerebral cortex and compared with that of area 17. Blocks of areas 17 and 18 came from the same brains and this allowed the comparison of 1) neuronal and glial numerical densities through the whole cortical depth with calculation of the neuron/glia ratio, 2) neuronal and glial numbers under one square millimeter of cortical surface, and 3) neuronal numerical densities in three groups of identified layers. The mean neuronal density is approximately 40,000 neurons/mm3 in area 17 and 31,500/m3 in area 18. The mean glial density is around 27,000/mm3 in area 17 and 32,000/mm3 in area 18. This gives a neuron/glia ratio of approximately 1.5 in area 17 and of 1.0 in area 18, but the total cellular density is similar in both areas. There are about 90,000 neurons and 64,000 glial cells under one square millimeter of cortical surface in area 17, and some 73,000 neurons and 74,000 glial cells in area 18. The higher neuronal density in area 17 is found through the whole depth of cortex and does not seem to be more pronounced in layer IVc of area 17 compared to layer IV in area 18 than in the groups of layers II-III and V-VI.

Adolescent↗

PubMed1989

Immediate reconstruction after subcutaneous mastectomy.

We describe an improved technique for subcutaneous mastectomy using two surgical approaches, one through a short axillary incision and the other through an inframmary incision. Pathological breast tissue is removed from the prepectoral space through the lower incision and a silicone implant is placed in the retropectoral space through the axillary approach. A further modification is described using a laterally rotated inframmary dermis flap to reinforce the lateral margin of the retropectoral space containing the prosthesis.

Adult↗

PubMed1989

Functional morphology in the inferior colliculus of the marmoset.

The inferior colliculus of the marmoset was studied in sections prepared by Nissl and Golgi techniques. As in other primates and subprimates it can be divided into a central nucleus (CN) and a cortex, further divisible into dorsal cortical and lateral zones. Afferent fibres enter CN from the lateral lemniscus and fan out from posteroventrolateral to anterodorsomedial, forming a set of laminae along which neuronal somata and dendrites tend to be aligned. Neurons are commonly bitufted or bipolar, and sometimes multipolar, with dendritic arbors oriented along the laminae. Other axons cut across the laminae and are probably efferent fibres destined for the brachium of the inferior colliculus en route to higher levels. The cortex is composed of a variety of bipolar and multipolar neurons and is not laminated. Injection of 2-deoxyglucose while exposing the marmoset to auditory stimulation demonstrates that tones at 4 and 30 kHz cause labelling along the laminae near, respectively, the dorsolateral and ventromedial limits of CN.

Animals↗

PubMed1989

[Sources of thalamic afferent neurons, projecting into the suprasylvian gyrus of the dolphin cerebral cortex].

The sources of a thalamic input to different loci of the suprasylvian gyrus (SSG) of the porpoise (Phocaena phocaena) cortex were studied by means of the retrograde HRP and fluorescent tracing methods. After injections of HRP into the anterior part of the SSG most cells were labelled in the lateral part of the ventrobasal complex. Some cells were also labelled in the ventroposteroinferior nucleus, posterior nucleus and caudally in the ventral parvocellular medial geniculate (MG). After injections of bisbenzimide in the middle part of the SSG many labelled cells were found in the ventral parvocellular MG and in the inferior pulvinar. Less cells were labelled in the magnocellular MG, lateral pulvinar and posterior nucleus. After bisbenzimide injection into the posterior part of the SSG the similar distribution of labelled cells was found but a sheet of labelled cells was shifted more laterally.

Animals↗

PubMed1988

Postnatal development of dendrites of relay neurons in the lateral geniculate nucleus of the marmoset (Callithrix jacchus): a quantitative Golgi study.

Dendrites of multipolar relay neurons in the lateral geniculate nucleus of the marmoset (Callithrix jacchus), at various ages from birth to adulthood, were studied in rapid Golgi preparations. The dendrites were analyzed by means of three-dimensional computer reconstructions and decomposed into intermediate and terminal segments, both of which were further classified according to their centrifugal order. Measurements were made of the number of segments per dendrite, the total length of dendrites, and the mean length of intermediate and terminal segments. In adult marmosets, there are four stem dendrites on average per neuron, and each dendrite divides into a mean of 14 segments. Between birth and 6 weeks of age, the mean dendritic length doubles, mainly because of changes in terminal segments. There is a significant decrease in dendritic length into adulthood. The total number of stem dendrites does not change after birth, but during the first postnatal week dendrites lose distal segments, after which there is a significant increase in the number of segments of orders 3 to 7. The mean length of intermediate segments does not change with age, nor with order, whereas the length of terminal segments increases from 50 to 120 microns from birth to 6 weeks of age, and then decreases to the adult value of 80 microns. In conclusion, during the period of most rapid visual development, important morphological changes occur in geniculate relay-cell dendrites, involving essentially terminal segments. These observations correlate well with changes of geniculate volume and neuronal density.

Animals↗

PubMed1988

Topographic differences in retinal axons in the dorsal lateral geniculate nucleus of the rat: a quantitative reexamination using anterograde transport of horseradish peroxidase.

Retinal endings in the dorsal lateral geniculate nucleus (dLGN) of the rat were visualized by anterogradely transported horseradish peroxidase following injections in the optic tract. The morphological findings confirm the two types of retinal axons previously suggested by Golgi investigations. In the caudal third of the dLGN type 2b axons, with small dense clusters of boutons, are the only representatives of retinal fibres seen. In the rostral two thirds they are intermingled with the larger type 2a terminals, but tend to accumulate laterally, adjacent to the optic tract. This study supports the concept that large retinal ganglion cells probably give rise to 2a axons that may represent a Y-like channel, whereas 2b axons are derived from small ganglion cells, and may relay a W-like pathway.

Animals↗