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Biomedical subjects

N Kopp

Publications and source records attributed to N Kopp.

At least 91 records · Page 5Linked to original sources
PubMed1987

The choice of the wavelengths in spectral analysis: an application to determine the composition of a tetraribonucleotide mixture.

We present a simple program running on a pocket computer allowing us to determine the order of importance of the wavelengths (regarding the accuracy of the results) in spectral analysis and to evaluate the absolute errors made on the determination of the concentrations of the constituents. We have applied this programme to the determination of the composition of a tetraribonucleotide mixture and have compared our results with other results published.

Microcomputers↗
PubMed1987

Substance P- and enkephalin-immunoreactive neurons in the hippocampus and related areas of the human infant brain.

Neurons strongly immunoreactive for substance P are present as subpopulations in the stratum oriens, pyramidal layer and polymorphic layer of the hippocampus of the human infant. Substance P immunoreactive terminals are numerous on other neuronal cell bodies in the polymorphic layer and over pyramidal cells of the subiculum and the CA1, 2 and 3 regions. There is a high density of substance P-immunoreactive axons in the granular layer. Enkephalin immunoreactive neurons are relatively few in number and are present in the polymorphic and pyramidal layers. The results indicate that substance P probably plays a major role in short range circuits in the human hippocampus and that intrinsic enkephalin neurons probably play a relatively minor role.

Brain Mapping↗
PubMed1987

Catecholamine synthesizing enzyme activity in brainstem areas from victims of sudden infant death syndrome.

In order to investigate whether central catecholaminergic neurons are altered in sudden infant death syndrome (SIDS), the activities of dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyltransferase (PNMT) were determined in nine brainstem areas from 19 victims of totally unexplained SIDS (tSIDS), 9 victims of partially unexplained SIDS (pSIDS) and 8 control infants. The distinction between tSIDS and pSIDS was made according to the results of the autopsy. They were totally negative for the tSIDS victims, while minor pathological alterations were found in pSIDS victims. In both tSIDS and pSIDS victims, the PNMT activity was significantly decreased in the medullary C2m and C21 areas and in the nucleus medullae oblongatae centralis. In the C21 area only DBH activity was decreased. Further, in the nucleus ambiguus PNMT activity was decreased in tSIDS, while DBH was lowered in pSIDS victims. No significant modifications were found in the areas from the dorso-lateral pons (locus coeruleus, Kolliker Fuse and parabrachialis nuclei). Thus, in the two groups of SIDS victims the capacity to synthesize adrenaline was decreased in some medullary areas. It is considered that these biochemical alterations are related to the abnormal central respiratory and arousal control, which is thought to be present in SIDS.

Brain Stem↗
PubMed1986

Neurotensin immunoreactive structures in the human infant striatum, septum, amygdala and cerebral cortex.

Neurotensin immunoreactive (NT-IR) neuronal perikarya are present in small numbers in the bed nucleus of the stria terminalis, lateral olfactory stria, substantia innominata, caudate nucleus and putamen of the human infant forebrain. Larger numbers of perikarya are present in the amygdala and related structures. NT-IR axons are present in the medial septal area, bed nucleus of the stria terminalis, caudate nucleus, putamen and amygdala. The cerebral cortex contains a rich network of NT axons with an accentuation in layer II. This network appears to be derived from bundles of axons which traverse the deep white matter from the thalamus.

Amygdala↗
PubMed1986

TRH and LH-RH distribution in discrete nuclei of the human hypothalamus: evidence for a left prominence of TRH.

Thyrotropin-releasing hormone (TRH) and luteinizing hormone-releasing hormone (LH-RH) have been measured by radioimmunoassay in individual human hypothalamic nuclei. A significant lateralization has been found for TRH in the ventromedial, dorsal and paraventricular nuclei, with higher concentration in the left side. In contrast LH-RH values did not differ between the left and the right side. This finding represents an additional example of cerebral specialization and the first report of lateralized peptide distribution in the human hypothalamus.

Adult↗
PubMed1986

Neurotensin immunoreactivity in the human cingulate gyrus, hippocampal subiculum and mammillary bodies. Its potential role in memory processing.

Neurotensin immunoreactive neurons comprise the majority of large perikarya in the human subiculum and project axons to the alveus, fimbria, fornix and neuropil of the mammillary bodies. These regions are prominently involved in conditions such as Wernicke's and Alzheimer's disease in which memory is impaired. Neurotensin has potential significance as a peptide in a human brain circuit which may serve a role in memory processing.

Female↗
PubMed1986

Kappa opioid receptors in human lumbo-sacral spinal cord.

[3H]Etorphine and [3H]ethylketocyclazocine bind with high affinity (Kd between 0.25-2.0 nM) to a single class of sites in human lumbo-sacral spinal cord. Other ligands such as [3H]morphine, [3H]dihydromorphine and [3H]D-Ala2, D-Leu5-enkephalin (DADLE) did not bind to significant number of sites under our incubation conditions. Ligand selectivity pattern strongly suggests that [3H]etorphine labels kappa opioid binding sites in the human lumbo-sacral spinal cord since benzomorphans and oripavines are much more potent than mu and delta agonists. Furthermore, [3H]etorphine and [3H]ethylketocyclazocine binding is sensitive to high concentrations of DADLE suggesting that these sites are of the kappa 2 sub-type. Finally, the visualization of these sites by receptor autoradiography demonstrates that they are mainly concentrated in lamina II and III of the dorsal horn. Moderate densities of sites are present around the central canal. Thus, it is possible that kappa opioid binding sites could be involved in the control of sensory and autonomic functions in the human lumbo-sacral spinal cord.

Adult↗
PubMed1986

[Benzodiazepine receptors in the hippocampus of suicides].

The characteristics of benzodiazepine binding sites (distribution, number, affinity) were defined on frozen sections of suicide's hippocampus (death by hanging) labeled with 3H flunitrazepam and compared to data previously obtained on control brains. The study was carried out qualitatively by autoradiography (distribution) and quantitatively by a biochemical technique (number and affinity). As a whole, the characteristics of BZD binding sites were not modified in relation to controls, except for a very slight decrease in affinity of subtype I.

Adolescent↗
PubMed1985

Autoradiographic and quantitative study of benzodiazepine-binding sites in human hippocampus.

Benzodiazepine-binding sites were studied on frozen sections of 5 human hippocampi, using autoradiographic and biochemical techniques. The affinity, density, distribution and heterogeneity (two types) of sites were investigated using [3H]flunitrazepam as a ligand, clonazepam or C1 218872 as displacing agents. The autoradiographic images evidence a differential distribution of the binding sites in the histologic layers of the hippocampus. Subtypes I and II coexist in the same proportion in the three layers exhibiting the highest densities of binding sites (stratum granulosum and pyramidale, deep layer of stratum radiatum). The Kd, Bmax and Ki values found here are analogous to those described in animal studies, but the anatomical distribution of the sites in human hippocampus seems to differ slightly from that previously described in that of the rat.

Adolescent↗
PubMed1985

Adrenergic neurons in human brain demonstrated by immunohistochemistry with antibodies to phenylethanolamine-N-methyltransferase (PNMT): discovery of a new group in the nucleus tractus solitarius.

Adrenaline neurons in human brain were demonstrated by immunohistochemistry using antibody to phenylethanolamine-N-methyltransferase (PNMT), the final enzyme in the pathway of adrenaline synthesis, using fixed frozen sections and a highly sensitive free floating technique which utilizes metallization. Small densely packed PNMT-immunoreactive neurons were observed to form a nucleus lying just ventrolateral to the area postrema and in the dorsal part of the nucleus tractus solitarius. Larger adrenergic neurons were also present in and around the lateral reticular nucleus and in relationship with the dorsal motor nucleus of the vagus in regions equivalent to the C1 and C2 groups in rats. Longitudinally oriented PNMT-positive axons constitute a subset of tyrosine hydroxylase-immunoreactive axons in the dorsomedial reticular formation.

Adrenergic Fibers↗
PubMed1984

[Neuropathy with contractures evoking the stiff-man syndrome. Latent solitary plasmacytoma].

A further case of apparently primary sensorimotor neuropathy is reported. The patient, a 31-year-old man, developed the syndrome after a 4-year history of a solitary vertebral plasmocytoma revealed by post mortem examination. Circulating monoclonal immunoglobulin and specific anomalies on nerve biopsy were absent. The condition became progressively worse, with initial and predominant autonomic nervous system anomalies. After 3 years, contractures of the limbs and paravertebral muscles, with painful paroxysmal attacks suggestive of the stiff-man syndrome appeared. Pathology confirmed the severity of the root lesions with diffusion to the cranial nerves. Reflex tests could not be conducted but the semiologic characteristics and the efficacity of baclofen were distinctive of continuous muscle fiber activities reported in some peripheral neuropathies. This case was comparable to some reported ones of interneuron rigidity.

Adult↗
PubMed1984

Immunohistochemical study of the catecholaminergic systems in the lower brain stem of the human infant.

The study of catecholaminergic (CA) systems in the lower brain stem was undertaken in the infant. A method of indirect immunohistofluorescence using antibodies to tyrosine-hydroxylase (TH) was applied to five brains from infants whose deaths had no neurological cause; two brains were submitted to fully systematic investigation. A topographical and morphocytological analysis of the CA systems was carried out on horizontal serial sections. A neuronal map is shown presenting four bulbar and four pontine sections. The disposition of the main CA groups (i.e. A1, A2, locus coeruleus) was found to be consistent with the data provided by the literature concerning the human foetus and the adult. Topographic differences and peculiarities are emphasized in the infant. Mapping of phenylethanolamine N methyltransferase (PNMT) positive neurons was performed in one plane of section of mid-medulla. This technique might usefully be applied to the exploration of putative diseases of bulbopontine CA systems, such as the sudden infant death syndrome and central blood pressure disorders.

Brain Mapping↗
PubMed1984

[X-ray scanning in Marchiafava-Bignami disease].

CT scan in 4 patients with Marchiafava-Bignami's disease in its acute alcoholic form, who died after 12, 18, 30 and 50 days respectively, demonstrated large symmetrical bilateral hypodense areas in the hemispheric white substance. These areas were either widespread or more marked posteriorly, and were independent of the corpus callosum. Pathologic examination of the brains showed necrotic regions, often with cavities, or areas of demyelinization of the centrum ovale correlating with the hypodense areas as seen on CT scans. In two cases CT scan further showed regions of linear hypodensity in front of and medial to the frontal ventricular horns which could have corresponded to the corpus callosum necrosis found on the brain sections. CT scan can thus contribute to the diagnosis of Marchiafava-Bignami's disease.

Acute Disease↗