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Biomedical subjects

J H Rogers

Publications and source records attributed to J H Rogers.

At least 19 recordsLinked to original sources
PubMed1992

Immunohistochemical markers in rat brain: colocalization of calretinin and calbindin-D28k with tyrosine hydroxylase.

Many dopaminergic cells of the substantia nigra are known to contain the calcium-binding proteins calretinin and calbindin-D28k. Catecholaminergic cell groups throughout the rat brain were therefore examined by two-colour immunofluorescence to determine whether they too contained these calcium-binding proteins as well as tyrosine hydroxylase (TH). Some TH+ cell groups are mostly positive for both calretinin and calbindin, notably in the ventral tegmental area, the interfascicular nucleus, and parts of the substantia nigra. Other TH+ cell groups in the midbrain, hindbrain and hypothalamus are very diverse; different cell groups are positive for calretinin, or calbindin, or both, or neither. In the olfactory bulb, entirely separate sets of periglomerular cells are positive for TH, calretinin and calbindin. However, there is considerable heterogeneity in calcium-binding protein expression within most cell groups, even in the substantia nigra. This could be a sign that calcium-binding proteins are regulated according to aspects of neuronal activity.

Animals↗
PubMed1992

Immunohistochemical markers in rat cortex: co-localization of calretinin and calbindin-D28k with neuropeptides and GABA.

Calretinin and calbindin-D28k are two calcium-binding proteins which are present in separate populations of interneurons in cerebral cortex and hippocampus. To identify these cells with the populations expressing different transmitters, two-colour immunofluorescence was done with antibodies against the calcium-binding proteins plus antibodies against vasoactive intestinal peptide (VIP), somatostatin (SRIF), or gamma-aminobutyric acid (GABA). In neocortex, calretinin is partially co-localized with VIP (especially in the deeper layers) and is not co-localized with SRIF. Calbindin is largely co-localized with SRIF, and not with VIP. Both calretinin and calbindin are partially co-localized with GABA. In piriform and entorhinal cortex, the patterns resemble those in neocortex. In hippocampus, preliminary data indicate greater heterogeneity, especially in the ventral part; at least a few double-positive cells are present for every combination of calcium-binding protein and neuropeptide. These results expand the known diversity of local-circuit neurons in cortical regions.

Animals↗
PubMed1992

Calcium-binding proteins in the nervous system.

Among the many calcium-binding proteins in the nervous system, parvalbumin, calbindin-D28K and calretinin are particularly striking in their abundance and in the specificity of their distribution. They can be found in different subsets of neurons in many brain regions. Although it is not yet known whether they play a 'triggering' role like calmodulin, or merely act as buffers to modulate cytosolic calcium transients, they are valuable markers of neuronal subpopulations for anatomical and developmental studies.

Action Potentials↗
PubMed1992

Calretinin in rat brain: an immunohistochemical study.

Calretinin is a calcium-binding protein related to calbindin-D28k; both are present in different though overlapping sets of neurons in brains of birds and mammals. We describe in detail the pattern of calretinin immunoreactivity in the rat brain. As in chick brain, calretinin immunoreactivity is abundant in various sensory pathways (particularly certain cells and fibres of the cochlear nuclei and olfactory bulb), in the heterogeneous parts of the brainstem and in parts of the hypothalamus. Many primary sensory fibres are strongly positive. Major groups of calretinin-positive neurons also include the thalamic reticular nucleus, triangular septal nucleus, lateral mammillary nucleus and substantia nigra pars compacta. Many other calretinin-positive cells are recognizable as local inhibitory neurons. Calretinin is absent from all but a few cells in the cerebral cortex, and is never found in motor neurons. There are also some distinctive positive structures whose identity is uncertain, notably irregular "shells" of cells and fibres around the thalamus and in the amygdala and an unnamed cell type in the vestibulocerebellum.

Animals↗
PubMed1992

Calretinin and calbindin-D28k in rat brain: patterns of partial co-localization.

Calretinin and calbindin-D28k are homologous calcium-binding proteins, each present in a variety of neurons in the brain. Their distributions in the rat brain have been compared at the cellular level to determine whether they tend to occur in the same or in different cells, and to determine whether calbindin-positive cells show any common features once crossreaction with calretinin has been eliminated. The results show great heterogeneity. Most cells which contain one of the proteins do not contain the other, but many cells do contain both; even in the ventral cochlear nucleus, where there is abundant calretinin and most calbindin-like immunoreactivity is due to crossreaction, a few cells contain both proteins. In the substantia nigra and ventral tegmental area, many cells are double-positive but some only contain one or the other protein. Only the triangular septal nucleus is uniformly positive for both proteins. Cells which look like local-circuit neurons in many forebrain areas (cortex, hippocampus, olfactory bulb, anterior olfactory nucleus) are exclusively positive for either calretinin or calbindin, in spite of their similar morphology. In the more heterogeneous parts of the brain (including hypothalamus central gray and substantia gelatinosa), there are mixtures of calretinin-positive, calbindin-positive, and double-positive cells. In comparison with previous data on the chick, some aspects of the distributions are conserved, but double-positive cells are more frequent in the rat. The degree of heterogeneity observed, even within comparatively well-defined neuronal populations, makes it difficult to infer in what neuronal properties these proteins could be involved.

Animals↗
PubMed1992

The use of ventilation tubes and the incidence of cholesteatoma surgery in the paediatric population of Liverpool.

Many surgeons believe that grommet insertion has reduced the incidence of cholesteatoma and thus radical mastoidectomy. Several causes for this trend have been postulated, including the increased use of ventilation tubes to treat otitis media with effusion. We have studied the number of operations for cholesteatoma, together with the number of ventilation tube insertions in the paediatric population of Liverpool, over a 28-year period between 1963 and 1990. There was a decline in the number of operations for cholesteatoma and an increase in the use of ventilation tubes, but there was no significant correlation between the two. This suggests that other factors are responsible for the decline in surgery for cholesteatoma.

Adolescent↗
PubMed1991

Parvalbumin-, calretinin- and calbindin-D28k-immunoreactivity and GABA in a forebrain region involved in auditory filial imprinting.

The distribution and morphology of neurons containing the Ca-binding proteins parvalbumin (PV), calbindin-D28k (CaBP) and calretinin (CaR) are described in a rostral forebrain region (MNH) of the chick, known to be involved in auditory filial imprinting. PV immunoreactivity is chiefly a marker for numerous large to medium-sized neurons in the neostriatal part of MNH. They show patchy staining of their dendrites, but PV-positive spines are not visible. CaBP is represented in a different neuron population with on the average slightly smaller-sized somata, which carry long, spiny, CaBP-positive dendrites. In contrast to PV and CaBP, CaR immunoreactivity is a marker chiefly for neuropil in MNH but only for few stained neurons. They may be spiny and show the largest size variations. The density of CaR-immunoreactive neuropil is highest in the hyperstriatal part of MNH. Double immunostaining for PV and CaBP reveals that these proteins are expressed mostly in different neuron populations, with only few neurons containing both proteins. These neuron populations appear to form an interconnected network within MNH. A possible relationship between the expression of either Ca-binding protein and the presence of the inhibitory transmitter GABA is also examined. The GABA-antibody labels scattered, very small to medium-sized neurons and dense punctate neuropil. The comparison of the area histograms of somata reveals an overlap with all 3 Ca-binding protein containing cell populations, except for a large proportion of small GABA-positive neurons. The characteristics of immunostained neuron populations are compared to the previously described 3 Golgi-types of neurons in MNH, and possibilities of a functional implication of the proteins in MNH plasticity are examined.

Acoustic Stimulation↗
PubMed1991

Calretinin and calbindin in the retina of the developing chick.

Calretinin and calbindin-D28k are two calcium-binding proteins that are present in largely different sets of nerve cells in the central nervous system. Their appearance during development of the chick retina was studied by immunohistochemistry and Western blots. The patterns are mature one day before hatching. Each cell type acquires its characteristic calcium-binding protein several days after its differentiation has started, but in most cases before morphological maturation is complete. There is also an early phase of calbindin immunoreactivity in many immature amacrine cells, and of calretinin immunoreactivity in the presumptive photoreceptor layer, suggesting that these proteins may have distinct functions in differentiating cells.

Animals↗
PubMed1990

The role of introns in evolution.

What are the roles of 'classical' introns in the evolution of nuclear genes, and what was the origin of these introns? Exon shuffling has been important in the evolution of cell surface and extracellular proteins, but the evidence for it in respect of intracellular proteins is weak. Intron distributions imply that some introns have been removed while others have been inserted in the course of evolution: ancestral patterns of introns may thus have been obscured. Recent evidence on the self-splicing and reverse-splicing abilities of Group II introns supports the hypothesis that these could have been the ancestors of classical introns.

Animals↗
PubMed1990

Inter-arytenoid glottic bar following intubation.

Inter-arytenoid glottic bar is a rare complication of prolonged endotracheal intubation. We present two such cases and their treatment. The aetiology of this complication is multifactorial and involves local factors--local trauma, movement of the endotracheal tube within the larynx, infection, and anatomical influences--together with systemic factors such as in our two cases. The relative importance of these factors is discussed. A comment is also made on the use of a pre-operative topogram and the importance of an ENT assessment in patients with airway problems following prolonged intubation.

Adolescent↗
PubMed1989

How were introns inserted into nuclear genes?

There is now abundant evidence that many introns have been inserted into nuclear genes after the divergence of multigene families, sometimes in a semi-regular pattern with respect to pre-existing domains. This note examines ways in which these insertions might have occurred using known molecular mechanisms.

DNA Transposable Elements↗
PubMed1989

Two calcium-binding proteins mark many chick sensory neurons.

The first immunohistochemical results with a new neuronal calcium-binding protein, calretinin, are presented. Calretinin is related to the 28,000 mol. wt calcium-binding protein, calbindin, and a survey of the chick brain by in situ hybridization has identified the brain nuclei that expressed the genes for the two proteins [Rogers J.H., J. Cell Biol. 105, 1343 (1987)]. Now, antisera have been raised against calretinin fusion proteins in order to visualize individual neurons. The antisera have been used in an immunohistochemical survey of calretinin and calbindin in the chick sensory nuclei and ganglia, where these two proteins are found to be particularly prevalent. In the central nervous system, they are seen in many secondary sensory neurons and local circuit neurons, the two proteins being almost always in separate cells. However, in ganglion cells of the spinal nerves, inner ear, and retina, they are often expressed together. Their distribution in the brain is generally different from that of a third calcium-binding protein, parvalbumin. These proteins may modulate many important calcium-dependent processes in neurons, and probably have multiple functions.

Animals↗
PubMed1989

Immunoreactivity for calretinin and other calcium-binding proteins in cerebellum.

Two calcium-binding proteins, calbindin and parvalbumin, have been reported to be abundant in Purkinje cells and other cell types in the cerebellum. Immunoreactivity for a related protein, calretinin, is now reported in cerebellum of chick and rat. In the chick, antibodies against calretinin stain mossy fibres throughout, and climbing fibres in a distinct group of folia. They also stain several cell types in the molecular layer. As there is no detectable calretinin mRNA in the cerebellar cortex, this cellular staining may be due to cross-reaction with an unknown antigen. In the rat, antibodies against calretinin stain the Lugaro cells, and some granule cells in lobe X; they also give weak staining of all the granule cells in the other lobes. Thus almost all the neuronal cell types in the cerebellum show immunoreactivity for at least one of the calcium-binding proteins in one or both species.

Animals↗
PubMed1989

Attitudes to tympanometry.

A postal questionnaire revealed the widest possible spectrum of opinion regarding tympanometry. The reasons are discussed.

Acoustic Impedance Tests↗
PubMed1988

Down's syndrome with lingual tonsil hypertrophy producing sleep apnoea.

A 12-year-old girl is presented with Down's syndrome and lingual tonsillitis causing sleep apnoea. In order to overcome her sleep apnoea she adopted a functional sleeping posture. The sleep apnoea was successfully treated by a single staged lingual tonsillectomy without preliminary tracheostomy. A return to a normal sleeping posture occurred spontaneously in the early post-operative period.

Child↗
PubMed1987

Sequence of carbonic anhydrase II cDNA from chick retina.

Sequences of three cDNA clones for carbonic anhydrase II (CA-II) from chick retina are presented. The longest cDNA clone encodes all but the first three amino acids of CA-II, and the encoded sequence generally agrees with published fragments of CA-II sequence from chick red blood cells. It is 70% identical to human CA-II; the active-site residues are conserved, but the chick protein has six extra cysteines. There is a long 3'-untranslated region which contains a second open reading frame, but this is not conserved. There appears to be a single CA-II gene in the chick. Some anomalies in cDNA synthesis and in Bal31 deletion are noted.

Amino Acid Sequence↗