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Biomedical subjects

M Berry

Publications and source records attributed to M Berry.

At least 307 records · Page 17Linked to original sources
PubMed1984

The injury response of nerve fibres in the anterior medullary velum of the adult rat.

The injury response of myelinated central nervous system (CNS) axons was documented in the anterior medullary velum (AMV) of the adult rat. Study of silver-stained AMV whole-mounts revealed sprouting of injured axons as early as 14 h post-lesion (hpl), with a complex network of fibres formed by 48 hpl. Signs of fibre degeneration were also apparent from 48 hpl, increasing in extent until 15 days post-lesion (dpl). Fragmentation was largely confined to specific fibre bundles, constituted by the distal portions of severed axons. Although some degeneration of regenerated axons was evident from 15-20 dpl, many remained intact beyond this time, particularly in the area adjacent to the exit of the trochlear nerve, where most regenerated fibres penetrated the ipsilateral trochlear nerve. Counts of HRP filled neurons in the trochlear nucleus after injection of the superior oblique muscle showed that axons entering the IVth nerve rootlet were exclusively ipsilateral trochlear fibres. Less than 50% regenerated; most other severed axons degenerated. The few axons remaining in the AMV may have been fibres, undamaged by the original lesion, which normally course longitudinally through the ipsilateral AMV. These results show that IVth nerve fibres preferentially enter IVth nerve rootlets and, in so doing, survive the effects of injury. Most other CNS axons in the AMV which do not enter the trochlear root probably degenerate.

Animals↗
PubMed1984

6-Hydroxydopamine induced ectopia of external granule cells in the subarachnoid space covering the cerebellum. II. Differentiation of granule cells: a scanning and transmission electron microscopic study.

The present report describes the morphological differentiation of ectopic granule cells from external granule cells that have been induced to escape from the cerebellar cortex into the subarachnoid space by injecting neonatal rats with 100 microgram 6-hydroxydopamine (6-OHDA) into the cisterna magna. The following cell types were observed in the period between 5 and 25 days postinjection (dpi): (1) unipolar cells with one process bearing a growth cone at its tip; (2) bipolar cells with two thin beaded processes originating from opposite cell poles, bearing growth cones at their tips; (3) bipolar cells with a T-like process at one pole and a short process lacking a terminal growth cone at the opposite pole; (4) multipolar cells with one thin beaded process and two or more short processes bearing growth cones of a different morphology at their tips; (5) intermediate stages. In the late second week p.i., cell aggregates were observed that continually increased in size up to 30 dpi. On the basis of our light, transmission, and scanning electron microscopic findings, we interpret these cell types to be equivalent to the individual stages of granule cell differentiation that characterize axon formation, migration, and aggregation. In the period between 30 and 365 dpi, granule cells were almost exclusively organized into cell colonies of different sizes, but small cell clusters and single granule cells exhibited the scanning electron microscopic features of adult granule cells, i.e., a small spherical cell body, a single axon with parent axonal stem, T-junction, and parallel fiber, and dendrites engaged in synaptic glomeruli. The parallel fibers ran in fasciculi of different sizes, often parallel to each other, but without preferential orientation over the cerebellar surface. During migration and aggregation, the granule cells and their processes were associated with a substrate of glial sheets that in turn were connected to intracortical Bergmann glia fibers. Our findings indicate that (1) granule cells differentiate normally in an ectopic environment in the presence of glia, (2) ectopic Bergmann glia contain no directional information to guide aberrant migratory granule cells to their correct destination, (3) granule cells can survive outside the brain parenchyma for periods up to one year (the longest postinjection interval studied).

Animals↗
PubMed1984

Vertex analysis of Purkinje cell dendritic trees in the cerebellum of the rat.

All networks are made up of vertices (points interconnected by segments), which include terminals interconnected by terminal segments, nodes interconnected by link segments and the root point connected to the tree by the root segment. All nodes may be classified into unique types according to the number of terminal and link segments they drain. For example, there are three distinct dichotomous nodes, a 'primary' node draining two terminal segments, a 'secondary' node draining one terminal segment and a link segment, and a 'tertiary' node draining two link segments. The numbers of primary and tertiary nodes approximate to equality in large networks and thus the ratio of primary to secondary nodes defines topology. All higher order nodes ( trichotomous and beyond) may be resolved into dichotomous forms and incorporated into the analysis. Different forms of growth may thus be analysed by comparing the frequency distributions of nodes with those generated by computer simulated growth models. Moreover, all vertices can be ordered so that metrical parameters are easily incorporated and the hierarchical arrangements of vertices of different order discerned. The dendritic trees of 48 Purkinje cells, taken from folia along the primary fissure, were analysed using vertex analysis. The mean number of segments in Purkinje cell trees was 881 +/- 23 (s.e.) and mean total dendritic length 7959 +/- 233 (s.e.) micrometers. Segment lengths were longest over proximal segments but over most of the tree segment lengths were constant at 10 +/- 0.2 (s.e.) micrometers. Vertex, segment and terminal frequency distributions of equivalent orders were all normal with a slight positive skew. Peak frequencies were recorded at the 12th equivalent order. The mean primary/secondary nodal vertex ratio was 0.93 and the proportion of trichotomous branch points in the tree was 5%. Comparison of the frequency distribution of all vertices with computer generated models showed that growth of the Purkinje cell was most closely simulated by a random terminal growth model, incorporating 5% trichotomy , in which the branching of high order terminals was more likely than low order terminals. It was concluded that growth of the Purkinje cell tree could proceed by random terminal branching with growth occurring preferentially over a front composed of terminals that are ascending through a corridor in the molecular layer whose margins are defined by neighbouring trees.

Animals↗
PubMed1984

Remodelling during development of the Purkinje cell dendritic tree in the mouse.

The development of the Purkinje cells in normal C57 mice was studied from 7-100 d post natum . The growth of the dendritic trees was analysed both metrically and topologically using the method of vertex analysis (Berry & Flinn 1983 a). Granule and PUrkinje cell counts were made so that Purkinje cell segment production could be correlated with the number of parallel fibres deposited. Both topological and metrical results indicate that from 7 to 30 d post natum the Purkinje cell dendritic trees expand massively; accounting for 87% of total segment elaboration, reaching their lateral boundaries by 12-15 d post natum and then advancing towards the pial surface. Continued lateral expansion is constrained by the proximity of dendrites from neighbouring trees. Growth proceeds upwards through the neuropil as a front of prolific random terminal branching with inhibitory forces acting at the edges of the growth corridor and behind the growth front to prevent overlapping of dendrites. By 30 d post natum all boundaries are reached and the size of the dendritic field is fixed. Trees averaged 711.2 segments +/- 21.45 with a mean distance from root to terminal segment of 133.5 +/- 2.9 micrometers. The Va/Vb vertex ratios and the levels of trichotomy during this period indicate that branching patterns deviate from pure random terminal additions in a dichotomous tree. There is opportunity for non-random growth at the areas of inhibitory action. Beyond 30 d post natum remodelling occurs within the arbor which involves segment loss in the subpial region (orders above 16) and segment elaboration within the tree (orders 8-16) causing increased density of dendrites and overlapping of segments. The frequencies of segments and terminals are restored to symmetrical distributions through the orders of the trees from the skewed distributions associated with the frontal advance in earlier growth. During remodelling the Va/Vb vertex ratios and percentage of trichotomous nodes are consistent with growth through dichotomous random terminal branching. Path lengths of 8 micrometers between each order are seen as regular increments throughout entire trees at 100 d post natum . The final tree produced is indistinguishable from a network grown entirely by random terminal dichotomous branching with some 6% trichotomy and a Va/Vb vertex ratios of 0.92. Granule cell number within the granular layer increases rapidly up to 15 d post natum after which cell death causes a decrease to stable levels beyond 30 d post natum .(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1984

The distribution of types I, III, IV and V collagens in penetrant lesions of the central nervous system of the rat.

The presence and distribution of types I, III, IV and V collagens within open lesions in the rat cerebrum have been demonstrated by immunofluorescent techniques. In the adult animal, types I and III collagens can be identified in the cicatrix from eight days onwards. Types IV and V collagens occur in the basement membrane of the glia limitans formed between the neuropile and the cicatrix and in the basement membranes of the blood vessels. In neonatal animals, less than eight days old at operation and allowed to recover for eight days, no type I or III collagens occur in the lesion and no types IV and V are present along the edge of the neuropile, because a glia limitans is not formed. In animals operated on when eight days old, the adult response is found in the cortex only, but when 16 days old the full adult response occurs in all parts of the lesion.

Animals↗
PubMed1984

A quantitative comparison of the reactions of retinal ganglion cells to optic nerve crush in neonatal and adult mice.

The response of neurons and glia of the ganglion cell layer of the retina to optic nerve crush was studied in adult and neonatal albino mice between 10-85 days post-lesion (dpl). The numbers of ganglion cells and glia surviving optic nerve transection were quantified using Nissl-stained retinal whole mounts. Large- and intermediate-sized ganglion cells were more sensitive to axotomy in the optic nerve than small-sized cells. About 80% of the former cells degenerated by 10 dpl in adult mice whilst 90-100% were affected in neonates. 40-60% of the small-sized ganglion cells survived in adults whilst in neonates, although a similar number escaped the effects of axotomy at 10 dpl, by 30 dpl only less than 10% remained. These aspects were reflected in the changes in the relative frequency distribution with time of ganglion cells in normal and lesioned mice. No significant alterations in glial cells in the ganglion cell and fibre layers of the retina were recorded at any time of lesioning the optic nerve.

Age Factors↗
PubMed1984

A qualitative comparison of the reactions of retinal ganglion cell axons to optic nerve crush in neonatal and adult mice.

The reaction of ganglion cell axons in the mouse retina to optic nerve crush was studied in adult and neonatal albino mice 10-85 days after operation, using silver-stained retinal whole mounts and sagittal sections of retina and optic nerve. In both adult and neonatal animals the majority of neural cells and axons degenerated; surviving neurons had small cell bodies. Degeneration was more marked in neonatal neurons compared to adult neurons. In the adult study, two populations of axonal sprouts growing from the ends of the severed ganglion cell axons were identified. One population, representing the large majority of fibres grew for up to 20 days after operation in the myelinated retinal stump of the optic nerve and then degenerated. A smaller number of axons grew for the whole duration of the study, initially in the inner plexiform area juxtaposed to the non-myelinated optic nerve head and peri-papillary region of the retina, but later invaded the entire retina. In the neonate, no evidence of axonal regeneration was seen, although transient axonal collateral sprouting of surviving ganglion cells occurred.

Age Factors↗
PubMed1984

Sex play and behavioural sexualization in the pig.

The patterns of adult copulatory behaviour can be observed in piglets. This sex play is more frequent in young boars than in young sows and reaches a peak during the second neonatal month. The castration of young boars within 5 min after birth (7 animals) eliminated the intense sex play of the second month. Gonadectomy at 30 days (3 animals) did not change mounting frequency during the second month, but reduced it during the third month. Castration at 60 days (7 animals) did not influence later mounting frequency. As adults (6 to 8 months of age), boars castrated at birth or at 30 or 60 days displayed typical female immobilization after an injection of 1 mg of oestradiol benzoate intramuscularly. In those castrated at 120 or 150 days of age (4 animals in each case) the female reaction was observed in only 35% of cases. No female response was observed in boars castrated at 180 days (3 animals). Sexualization of the nervous mechanisms of sexual behaviour in boars develops slowly and progressively during the prepubertal period and is independent of the evolution of sex play.

Age Factors↗
PubMed1984

Late post radiation necrosis and fibrosis of the larynx.

Radiation has been used to treat carcinoma of the larynx for some 60 years. We have seen some very late complications of radiation to this region. In this paper we present three patients who had radiation-induced necrosis and fibrosis 13, 19, and 22 years after initial treatment. The problem exists of diagnosing and differentiating perichondritis/fibrosis from recurrent carcinoma. However, many times it is impossible to make this distinction clinically, endoscopically, radiologically, or even pathologically. The pathogenesis, clinical features, and treatment of this rare late complication of radionecrosis and/or fibrosis are presented.

Adult↗
PubMed1983

Deposition of scar tissue in the central nervous system.

Standard parasagittal lesions were placed stereotactically in the cerebral hemispheres of neonatal and adult rats in order to compare scarring in the immature and mature animal. Lesions were examined by light and electron-microscopy and immunofluorescence to study the astrocyte reaction, collagen deposition, and the formation of the basement membrane of the glia limitans. Normal mature scarring characterized by the deposition of collagen, astrocyte end-feet alignment over a glia limitans, and the permanent presence of mesodermal cells (fibroblasts and macrophages) in the core of the lesion, does not occur in wounds before 8-10 days post-partum (dpp). Instead there is no deposition of collagen, and only a transitory astrocyte response occurs with the formation of an interrupted glia limitans. These latter features disappear with time so that the wound is ultimately obliterated by the growth of axons and dendrites through the lesion. Mature scarring is attained over 8-12 dpp when increasing amounts of collagen are deposited and a continuous permanent glia limitans is formed. The acquisition of the mature response to injury from 8-12 dpp may be correlated with the presence of increasing titres of a fibroblast growth factor (FGF), derived from autolytic digestion of injured brain tissue. We have investigated FGF activity using a 3 T 3 fibroblast tissue culture assay to detect mitogenic activity in brain extracts from rats lesioned at different ages and from leukodystrophic mice which have no myelin. Our results show that high titres of FGF are present in the developing brain long before myelination commences, and that normal levels of FGF are found in the brains of leukodystrophic mice which have no myelin. Scarring in brain lesions in these mutants is quite normal.

Animals↗
PubMed1983

6-OHDA-induced ectopia of external granule cells in the subarachnoid space covering the cerebellum. Genesis and topography.

The present report describes the genesis, development and topographical distribution of ectopic cells of the external granular layer in the subarachnoid space covering the rat cerebellum. Following one intracisternal injection to newborn rats of 100 micrograms 6-hydroxydopamine (6-OHDA), the meningeal cells degenerate and are removed by phagocytosis within 24 h post injection (p.i.), leaving the cerebellar cortex without a pia-arachnoid cover. Defects appear in the basal lamina investing the cerebellar cortex 3 to 5 days p.i., and both external granule cells and 'sprouts' from Bergmann-glia endfeet grow into the subarachnoid space. The latter form large, flat glial lamellae and cover extensive areas of the denuded cerebellar surface, although they do not form a glial scar over the exposed neuropil of the cerebellar cortex. The numbers of ectopic external granule cells increase within the subarachnoid space both by proliferation and a continuous efflux of cells from the cerebellar cortex. They migrate, aggregate, and ultimately develop into granule, stellate and basket cells, the morphology of which is indistinguishable from their counterparts in situ; they make specific afferent and efferent connections, both among themselves and with the underlying cerebellar cortex and brainstem. The distribution of ectopic external granule cells and their derivatives is restricted to the anterior vermal fissures and the vermal-hemispheric junctions. The present results indicate that external granule cells and their derivatives are capable of both differentiating normally and surviving in the subarachnoid space if they become associated with glial cells and establish synaptic connections.

Animals↗
PubMed1983

Morphometric study of the development of Purkinje cell dendritic trees in the mouse using vertex analysis.

Vertices are the points in an arborescence which interconnect segments and comprise terminal or pendant vertices (Vp), nodal or branching points and the root point. Branching points may be dichotomous (Vd) or trichomtomous (Vt), etc., and are subdivided into distinct two-dimensional topological entities according to the number of terminal vertices they drain, i.e. Vds comprise primary vertices (Va), connecting two Vps; secondary vertices (Vb), connecting one Vp and one Vd or one Vt; and tertiary vertices (Vc), connecting either two Vds, two Vts or one Vt and one Vd. The four types of Vt (Va', Vb', Vc', Vd') similarly connect three, two, one and zero Vps respectively. Each Vt may be transformed into two Vds thus, Va' = Va + Vb; Vb' = Va/3 + 4Vb/3 + Vc/3; Vc' = Vb + Vc and Vd' = 2Vc. Analysis proceeds by transforming mixed trees containing varying proportions of Vds and Vts into entirely dichotomous branching structures. The topology is then defined by the Va/Vb ratio which has a unique value according to the mode of growth and the frequency of Vts. Vertices are ordered by a centrifugal technique. The frequency distribution of vertices of different order allow the changes in growth characteristics and in remodelling to be detected within particular regions of the tree. Metrical parameters are readily incorporated into the analysis since all vertices are interconnected by segments of finite length and are given the same order magnitude as the vertex they drain. The analytical capabilities of the method are exemplified by its application to the study of growth and plasticity in the dendritic trees of Purkinje cells in the mouse. Growth is defined in metrical and topological terms and sites of reorganization within the mature tree are identified.

Aging↗
PubMed1982

Regeneration of ganglion cell axons in the adult mouse retina.

The hypothesis that regenerative failure of axons in the adult mammalian CNS is due to release of a growth inhibitor from injured oligodendrocytes and/or myelin2, predicts that regeneration of injured fibers would proceed unchecked in unmyelinated CNS regions. This prediction was borne out by observations on the stratum opticarum of the mouse retina. Axonal sprouts, first seen 14-16 h post-lesion (pl), continued growing until at least 100 days pl, well beyond the time at which regeneration fails in myelinated CNS regions.

Animals↗
PubMed1982

Stepwise isolation and properties of unstable Chinese hamster cell variants that overproduce adenylate deaminase.

Addition of coformycin (0.5 microgram/ml) to a culture medium containing adenine causes in Chinese hamster fibroblasts a lethal depletion of IMP. Resistant variants have been recovered, some of which exhibit increased adenylate deaminase activity. (Debatisse et al., J. Cell. Physiol., 106:1-11, 1981). The selective medium was made more specific for the isolation of this class of variants by supplementation with azaserine. The hyperactive variants remained sensitive to coformycin concentrations above that used for their selection and were unstable. Their frequency was not increased by ethyl methane sulfonate mutagenesis. The resistant phenotype and the increased activity of adenylate deaminase behaved as semidominant traits in hybrids. No change was detected in the Km for AMP, the cofactor requirement, or the chromatographic properties of adenylate deaminase in the variants. Through stepwise selection in media supplemented with increasing coformycin concentrations, unstable clones with adenylate deaminase activity up to 150-fold the wild-type level were isolated; from an unstable clone, a stable subclone with reduced resistance and enzyme activity was recovered. Evidence that increased adenylate deaminase activity is the manifestation of overaccumulation of the enzyme protein was supplied by the correlation of enzyme activity with the intensity of a protein band comigrating with purified adenylate deaminase during sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cell extracts. Several unidentified additional bands showed comparable quantitative changes. The striking similarity between the adenylate deaminase-overproducing lines and unstable dihydrofolate reductase-overproducing lines generated by gene amplification strongly suggests that the coformycin-resistant variants also resulted from amplification of an adenylate deaminase gene.

AMP Deaminase↗
PubMed1982

[Daylight development and mammography (author's transl)].

A "daylight" development system adapted for mammography has been employed over a period of 18 months. Rigid MR 50 Agfa-Gevaert cassettes were adapted for use in th Gévamatic L modular system. Compatibility of this mammography cassette with the unloading module of the Gévamatic system was ensured by the employ of an intermediate metallic frame, adaptable to the cassette and modifying its opening system. The modified apparatus appears to give reliable results which should incite manufacturers to adopt their "daylight" development systems to mammography examinations. Wider diffusion of these systems is probably limited by their current inability to be employed for mammography.

Humans↗