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Biomedical subjects

M Gay

Publications and source records attributed to M Gay.

At least 37 records · Page 2Linked to original sources
PubMed1987

Psychogenic habit cough: review and case reports.

Psychogenic habit cough--a condition that can be debilitating if it extends over a period of years--has been described in both pediatric and adolescent populations, but not in adults. The authors review the cases of 4 adult patients with this condition, review the available pediatric/adolescent literature, and make suggestions for the direction of future research. In some cases, psychogenic habit cough in adults can be successfully treated with a combination of psychotherapy, relaxation therapy, and speech therapy.

Adolescent↗
PubMed1987

Problem drug users known to Bristol general practitioners.

A 12-month prospective survey was undertaken of all 239 problem drug users known to general practitioners in Bristol and the doctors' attitudes towards them. The drug users were predominantly young, aged 15-35 years, and males outnumbered females by approximately two to one. Seventy-eight per cent had problems associated with opiates, almost invariably heroin, 10% had problems with stimulants (mainly amphetamine powder), and others had problems with hallucinogens, cannabis, barbiturates and solvents. Opiate dependence was the commonest single problem but ill health, hepatitis, psychiatric illnesses, relationship problems, work and financial difficulties were also frequently mentioned.There was a wide variation in the numbers of problem drug users seen by individual practices, which related both to the situation of the practice and the widely varying attitudes of the partners towards drug users and drug problems. General practitioners were aware of the grapevine that transmits news of their treatment to other users, and individual practices had typically evolved a general strategy for all drug users, to minimize arguments. General practitioners were asked their views about specialist services: they thought that services in the area for drug users were inadequate to help them and their patients in 58% of cases. Several suggestions were made for additional services which were needed.

Adolescent↗
PubMed1985

Response of murine spermatocytes to the metaphase-arresting effect of several mitotic arrestants.

Three mitotic arrestants, colchicine, Colcemid and vinblastine, were evaluated for their effects on producing meiotic arrest in the laboratory mouse. Colchicine is the most effective and its effect is both dose- and time-dependent. Treatment of mice with 40 mg/kg of colchicine for 3 h resulted in drastic improvement of the yield and quality of M-II figures. This treatment did not appear to increase the aneuploidy frequency in M-II's.

Aneuploidy↗
PubMed1985

Increased number of locus ceruleus noradrenergic neurons in the convulsive mutant quaking mouse.

Noradrenergic cell bodies in the locus ceruleus of the convulsive mutant quaking mouse and the control of the same strain were visualized using histofluorescence and tyrosine hydroxylase-like immunoreactivity. Cell counts performed with the two techniques gave closely similar results within each strain, indicating a 50% increase in the number of noradrenergic neurons in the midportion of the mutants' locus ceruleus when compared to the controls. This result gives histological support to the increased noradrenergic neurotransmission previously described in the brain of this mutant. Thus, the abnormally high activity of the noradrenergic system appears to be a primary effect of the mutation, associated with the convulsions of this animal model of epilepsy.

Adrenergic Fibers↗
PubMed1985

ECT in the presence of increased intracranial pressure and respiratory failure: case report.

Despite the safety of electroconvulsive therapy (ECT) in the presence of such potentially dangerous CNS disorders as CNS infections, brain tumor, and normal pressure hydrocephalus, increased intracranial pressure is still considered an absolute contraindication. In addition, although ECT has been administered to patients with pneumonia, it has never been used when respiratory failure is present. The safe and effective use of ECT in a patient in whom life-threatening refusal to cooperate with medical therapy appeared to be caused by a combination of depression and organic brain disease is reported.

Depression↗
PubMed1984

Morphology of primate's dopaminergic amacrine cells as revealed by TH-like immunoreactivity on retinal flat-mounts.

Dopaminergic (DA) cells have been revealed by immunohistochemical localization of tyrosine hydroxylase in the retina of cynomolgus monkey, chimpanzee and human. The DA neurons were visualized in cross-sections as well as in flat-mounts of retina. The comparison revealed a striking morphological similarity between the DA neurons in the three species. When observed in flat-mounts, they were of stellate type; when observed in cross-sections, except for a few displaced cells, they were unistratified amacrine cells branching in the outermost sublayer of the inner plexiform layer. Observations in sections suggested the existence of DA-interplexiform cells in ape and human retinas.

Animals↗
PubMed1984

Localized conserved regions of the S RNA gene products of bunyaviruses are revealed by sequence analyses of the Simbu serogroup Aino virus.

The complete nucleotide sequence has been determined for the S RNA of Aino virus, a member of the Simbu serogroup (Bunyavirus genus, family Bunyaviridae). The S RNA is 850 nucleotides long (2.76 X 10(5) daltons) and in the viral complementary sequence has a short 5' non-coding region of 34 nucleotides and a more extensive 3' non-coding region of 117 nucleotides. The 3'-5' complementarity of the Aino S RNA is about 25 residues long, depending on the arrangement. The Aino sequence predicts that, like snowshoe hare (SSH) and La Crosse (LAC) bunyaviruses (Bishop, D.H.L., et al. (1982) Nucleic Acids Res., 10, 3703-3713; Akashi, H. and Bishop, D.H.L. (1983) J. Virol. 45, 1155-1158), there are two S coded gene products, a nucleoprotein N, and a non-structural protein, NSS, that are read from overlapping reading frames in the viral complementary sequence. The Aino N primary gene product is composed of 233 amino acids (26.2 X 10(3) daltons) and is 45% homologous in sequence with that of LAC virus. The NSS protein of Aino virus is composed of 91 amino acids (10.5 X 10(3) daltons) and is 35% homologous in sequence with the LAC NSS protein. Unlike those viruses there are no uridylate tracts longer than 4 residues in the 5' non-coding region of the S viral RNA that could function as a template for polyadenylation of Aino S mRNA species.

Amino Acid Sequence↗
PubMed1983

Post-natal development of TH-like immunoreactivity in the rat retina.

The post-natal development of catecholaminergic neurons has been studied in the rat retina, using tyrosine-hydroxylase immunohistochemistry. The first TH-like immunoreactive cells were observed by the third post-natal day. The differentiation of neurons and the development of their processes continued until and after, the opening of the eyes (14-15th post-natal day). The catecholaminergic system was fully developed by three weeks of age. The use of retinal flat mounts treated with PAP-immunoperoxidase technique allowed a morphological observation of TH-like immunoreactive whole neurons.

Animals↗
PubMed1983

Tyrosine hydroxylase and methionine-enkephalin in the human mesencephalon. Immunocytochemical localization and relationships.

The immunocytochemical localization of tyrosine hydroxylase (TH) and methionine-enkephalin (met-enkephalin) was determined at two representative caudal and rostral levels of the human mesencephalon. Four main groups of catecholaminergic neurons were delineated, situated in the substantia nigra and the lateral, ventromedial and dorsomedial tegmentum, extending over several cytoarchitectonic divisions. They matched fairly well the dopaminergic cell groups described in monkey midbrain. TH-like immunoreactivity and neuromelanin were closely related in neurons of substantia nigra, but less so in the other groups. A widespread met-enkephalinergic innervation was observed in most areas containing catecholaminergic neurons. It followed a characteristic pattern: homogeneous and very dense in the lateral and posterior portions of substantia nigra; patchy and less dense in the other areas, the medio-ventral and periaqueductal gray being only sparsely innervated, in contrast to observations in rodents. Dopaminergic cell bodies surrounded by met-enkephalinergic varicosities were seen in most groups, particularly in the lateral substantia nigra and medioventral tegmentum. The topography of met-enkephali-like immunoreactive terminals in the substantia nigra was reminiscent of the distribution of neostriatal and pallidal afferents.

Aged↗
PubMed1983

Interference between bunyaviruses in Aedes triseriatus mosquitoes.

Inhibition of the replication of alternate California serogroup bunyaviruses in Aedes triseriatus mosquitoes has been observed for mosquitoes previously infected with La Crosse (LAC) virus. By contrast, prior infection of mosquitoes with LAC virus did not interfere significantly with the subsequent infection and replication of Guaroa bunyavirus (Bunyamwera serogroup), or heterologous viruses such as West Nile flavivirus, or vesicular stomatitis rhabdovirus.

Aedes↗
PubMed1982

Development of the dopaminergic innervation of the rat cerebral cortex. A light microscopic immunocytochemical study using anti-tyrosine hydroxylase antibodies.

A precise topographical analysis of the distribution of tyrosine hydroxylase-like immunoreactive processes was performed in the frontal, cingular and parietal cortex of the rat during late embryonic and early postnatal life. Until birth, labeled processes were only observed in the restricted cortical areas known to receive a dopaminergic innervation in the adult brain. Their distribution differed markedly from that of noradrenergic fibers as identified by their dopamine-beta-hydroxylase-like immunoreactivity. Thus we considered TH-like immunoreactivity to be a selective marker of the cortical dopaminergic innervation during late fetal life, at least with the antibody we used. With this marker, dopaminergic fibers were first detected in the anterior frontal cortex at day 16 of embryonic life (E16). They developed as two bundles passing medially and laterally to the ventricular layer without penetrating it. From E20 on, the terminal fields extended to the cingular and rhinal cortex, still being restricted to the intermediate zone. No fibers were visible in the lateral and dorsal frontal cortex at this time, nor in the cortical plate and molecular layer in any cortical area. At E21, rare labeled fibers were seen in the molecular layer of the medial frontal and cingular cortex. After birth, the terminal fields of the TH-containing fibers extended further caudally in the cingular cortex and also superficially in the cortical plate. Moreover, labeled axons now also appeared in the lateral frontal and parietal cortex where their density gradually increased. At P14, two different patterns of distribution were observed: a high density of TH-positive fibers in the cortical areas known to receive a dopaminergic innervation; a low density of fibers in the other cortical areas which represented noradrenergic fibers. Indeed these TH-containing presumed noradrenergic fibers were absent at P14 following a bilateral destruction of the locus coeruleus in 4-day-old pups.

Animals↗
PubMed1982

Long-term development of mesencephalic dopaminergic neurons of mouse embryos in dissociated primary cultures: morphological and histochemical characteristics.

In 13 and 15 day-old mouse embryos mesencephalic dopaminergic neurons could already be visualized at the level of the mesencephalic flexure by tyrosine hydroxylase immunocytochemistry at day 13. At this time, noradrenergic cells in the locus coeruleus area were not detectable. In most in vitro experiments, dissociated mesencephalic cells of 13 day-old embryos were grown in presence of serum. Four approaches were used to identify the dopaminergic neurons in vitro: fluorescence histochemistry of newly taken up exogenous norepinephrine, radioautography after labelling with (3H) dopamine, tyrosine hydroxylase-like immunoreactivity and fluorescence histochemistry of endogenous stores of catecholamines. Control experiments performed at various times in vitro with selective inhibitors of amine transport into dopaminergic, noradrenergic and serotoninergic neurons indicated that only dopaminergic neurons were detected by these various approaches, noradrenergic neurons being virtually absent from the cultures. The uptake of exogenous norepinephrine was detected already 24 h after plating and preceded the appearance of tyrosine hydroxylase-like immunoreactivity (48 h). The number of neurons revealed by these two techniques increased up to 4 and 10 days, respectively. Endogenous stores of dopamine were only seen after three weeks in vitro by fluorescence histochemistry. At this time, the same number of neurons was revealed whatever the method used. The presence of striatal target cells (co-cultures) affected neither the sequential appearance of the markers nor the number of dopaminergic cells. The two main types of dopaminergic neurons (fusiform and multipolar) described in vivo both in the substantia nigra (A9) and the ventral tegmental area (A10) of adult animals were identified in vitro and their development into well-differentiated neurons can be followed for up to six weeks. This in vitro system seems, therefore, to be particularly suitable for biochemical and electrophysiological studies of these dopaminergic neurons.

Animals↗
PubMed1982

Drug abuse monitoring: a survey of solvent abuse in the county of Avon.

1 An attempt to identify the extent of solvent abuse in the County of Avon by means of a multidisciplinary reporting system is described. 2 Particular attention was given to identifying abusers thought to be most at risks. 3 Altogether 304 young persons involved in solvent abuse were identified within a 6-month period. The ages of the solvent abusers ranged from 9 to 21 years and 77% were aged between 14 and 17 years. 4 Thirty-nine of the sniffers were found to be solitary users and were thought to have multiple problems and possibly a poorer prognosis than the group sniffers. 5 The problems of confidentiality and inter-agency conflict are discussed.

Adolescent↗