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Biomedical subjects

C Jackson

Publications and source records attributed to C Jackson.

At least 127 records · Page 7Linked to original sources
PubMed1994

Overlapping and distinct actions of the neurotrophins BDNF, NT-3, and NT-4/5 on cultured dopaminergic and GABAergic neurons of the ventral mesencephalon.

The neurotrophins brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5) were compared for their effects in promoting the survival and/or regulation of expression of phenotypic markers of dopaminergic and GABAergic neurons in cultures derived from embryonic rat ventral mesencephalon. Dopaminergic neuron number and phenotypic expression were monitored by tyrosine hydroxylase (TH) immunocytochemistry, and measurement of high-affinity dopamine uptake activity and dopamine content, respectively. High-affinity GABA uptake, glutamic acid decarboxylase (GAD) activity, and endogenous GABA content were used to detect GABAergic neurons. Seven days of treatment with either BDNF or NT-3 resulted in dose-dependent increases in the number of TH-positive neurons, with maximal responses of 3-fold and 2.3-fold, respectively. Dopamine uptake activity and dopamine content were similarly increased. The effects of BDNF and NT-3 on dopamine uptake activity showed no additivity. NT-4/5 treatment elicited the greatest increase (7-fold) in the number of TH-positive neurons, as well as a 2.6-fold increase in dopamine content. In marked contrast to BDNF or NT-3, NT-4/5 had no effect on dopamine uptake capacity. BDNF, NT-3, or NT-4/5 also produced dose-dependent elevations of 2-3-fold in GABA uptake activity. These effects were not additive. GAD activity was increased by BDNF (1.8-fold) and NT-3 (threefold) treatment, but not by NT-4/5, whereas GABA content was increased to a similar extent by all three neurotrophins. NGF had no effect on any of the parameters measured in this study. Northern analyses indicated that the mRNAs encoding TrkB and TrkC, the functional high-affinity receptors for BDNF and NT-4/5, and NT-3, respectively, are expressed in the substantia nigra of adult rat brain, as well as in cultures of developing ventral mesencephalon. Taken together, our results indicate that BDNF and NT-3 have broadly similar effects in promoting the survival and differentiated phenotype of both dopaminergic and GABAergic neurons of the developing substantia nigra. Although BDNF and NT-4/5 are thought to act through the same high-affinity receptor, TrkB, it is evident that these two neurotrophins have distinct as well as overlapping actions toward mesencephalic dopaminergic or GABAergic neurons.

Animals↗
PubMed1993

3-Carbamyl-N-allylquinuclidinium bromide. Effects on cholinergic activity and protection against soman.

3-Carbamyl-N-allylquinuclidinium bromide (CAB) was synthesized and evaluated for its pharmacological effects on cholinergic activity and for protection in vivo against soman toxicity in guinea pigs. This carbamylated derivative of N-allyl-3-quinuclidinol (NAQ), a potent inhibitor of high-affinity choline uptake, demonstrated stereospecific alterations of cholinergic function as well as protection against soman. The R-isomer, but not the S-isomer, of CAB inhibited erythrocyte acetylcholinesterase (AChE) and plasma pseudocholinesterase (pChE) in a concentration-response manner (IC50 = 25 and 29 microM, respectively). The R-isomer of CAB was also a more potent inhibitor of high-affinity choline uptake (IC50 = 4.8 microM) than S-CAB (IC50 = 63 microM). When R-CAB (10 mumol/kg, i.m.) was administered to guinea pigs 30 min prior to soman in conjunction with atropine (16 mg/kg, i.m.) given 1 min post-soman, the compound significantly reduced lethality up to 5 LD50S. This represents enhanced protection when compared to NAQ (up to 100 mumol/kg); the S-isomer of CAB failed to protect against soman intoxication. The results demonstrate that reversible inhibition of AChE with suppression of acetylcholine synthesis into a single compound, CAB, enhances the protection against organophosphates.

Acetylcholine↗
PubMed1993

Dreams of death: Von Weizsäcker's Dreams in so-called endogenic anorexia: a research note.

Viktor Von Weizsäcker's paper "Dreams in so-called endogenic Magersucht (anorexia," first published in the Deutsche Medizinische Wochenschrift in 1937 (translation in M. Kaufman & M. Heiman [1964]. Evolution of psychosomatic concepts: Anorexia nervosa: A paradigm (pp. 181-197), New York: International Universities Press, has been described as a noteworthy and historically important contribution to the recognition of anorexia nervosa as a psychosomatic illness. Von Weizsäcker analyzed the dreams of patients he was treating for "endogenous anorexia" (magersucht). He claimed that in the bulimic phase his patients experienced nightmares dealing with themes of death, but that in the anorectic phases of restricted eating more pleasant dreams dealt with themes of blissful contentment. The authors draw current attention to his work as another early example of the treatment of the theme of death and death symbolism in the literature on eating disorders, and suggest some reappraisal of von Weizsäcker's interpretations of his own material.

Anorexia Nervosa↗
PubMed1993

Themes of death: Helmut Thomä's "Anorexia nervosa" (1967)--a research note.

In the recent literature on eating disorders, little attention is usually given to the possible role played by heightened death fears and anxieties and failed death transcendence in the dynamics of patients who suffer from anorexia and bulimia nervosa. For reasons that remain unclear, early texts and articles in the literature do address death themes, particularly as they are discernible from patients' dreams and nightmares. Thomä's 1967 text Anorexia Nervosa may be interpreted as giving further illustration to this thesis.

Adult↗
PubMed1993

Depletion of murine CD8+ T cells in vivo decreases pulmonary clearance of a moderately virulent strain of Cryptococcus neoformans.

Host defense mechanisms to the important fungal pathogen Cryptococcus neoformans are complex and incompletely understood. From in vitro studies, we could expect CD8+ T cells to have the potential for both protective and suppressive effects on defense against cryptococci. The current study used the technique of in vivo subset depletion to determine the net effect of CD8+ T cells during actual infection. Mice depleted of CD8+ T cells by monoclonal antibody (YTS 169.4) injections were infected with the moderately virulent cryptococcal strain 613D by the intratracheal route, which mimics natural pulmonary infection. To ensure adequacy of depletion, T cell subsets were enumerated by flow cytometry in blood, spleen, lymph node, and lung. Specific elements of host defense were measured by clearance of cryptococci in vivo and by the response to cryptococcal antigens, both in vivo by delayed-type hypersensitivity (DTH) and in vitro by lymphocyte proliferation. We found that depletion of CD8+ T cells decreased pulmonary clearance of C. neoformans. CD8 depletion abrogated DTH without affecting antigen recognition or lymphocyte proliferation in vitro. These data demonstrate that the net effect of CD8+ T cells to a moderately virulent strain of C. neoformans is to enhance rather than suppresses host defenses. Abrogation of DTH suggests that CD8+ T cells contribute to the protective immunologic response to C. neoformans. It is possible that in hosts deficient in CD4 cells, such as patients with AIDS, the protective effects of CD8+ T cells could be stimulated by selected immunizing epitopes.

Animals↗
PubMed1993

A cholinergic interaction in alpha 2 adrenoceptor-mediated antinociception in sheep.

Intraspinal administration of alpha 2 adrenergic agonists produces analgesia, but clinical application of these agents is limited by dose-dependent sedation and hypotension. Recently, neostigmine has been demonstrated to counteract hypotension in sheep and enhance antinociception to tail flick in rats from spinally administered alpha 2 adrenergic agonists. We investigated this spinal interaction further in chronically prepared, conscious sheep, testing antinociception with a mechanical pressure stimulus on the forelimb. Clonidine produced dose-dependent antinociception which was antagonized by idazoxan and enhanced by neostigmine, although it was unaltered by methylatropine. Clonidine increased acetylcholine in cerebrospinal fluid, an effect potentiated by physostigmine and blocked by idazoxan. The highly lipid-soluble alpha 2 adrenergic agonists dexmedetomidine and clonidine produced antinociception, whereas the poorly lipid-soluble ST-91 (2,[2,6-diethylphenylamino]-2-imidazoline) produced antinociception only at much larger doses and did not affect cerebrospinal fluid levels of acetylcholine. In human volunteers, epidurally administered clonidine increased cerebrospinal fluid acetylcholine levels at the time of peak analgesia. These results support the existence of an interaction between alpha 2 adrenergic and cholinergic mechanisms of analgesia at the spinal level and underscore the importance of lipid solubility in the actions of spinally administered drugs in sheep.

Acetylcholine↗
PubMed1993

Marketing. I. Lessons in talking business.

The Welsh Office has invested thousands of pounds in a national training programme to help community nurse managers and field staff market their services to GPs, commissioning health authorities and the public. Catherine Jackson reports on the genesis of the project and the benefits to health visitors in the field.

Community Health Nursing↗
PubMed1993

Health promotion. Pitching the message at men.

Haringey health services beamed its safer sex message into millions of homes all over Britain. It was splashed across almost every national newspaper and got saturation coverage in the local press and on local radio. So how did they do it? Cath Jackson reports on a whole new ball game in health promotion.

Health Promotion↗
PubMed1993

Brain abscess in a goat.

A young goat was presented with a left spastic hemiparesis and general proprioceptive ataxia with postural reaction deficits, a right head tilt and positional nystagmus. Seizure-like activity was elicited by rapid changes in the position of the animal's head. The neurological signs and quality of the seizure activity suggested a lesion involving the medulla and possibly the cerebellum. A focal lesion at the level of the left cerebellar peduncles could explain the left hemiparesis and right paradoxical vestibular signs. A large encapsulated abscess was found at the confluence of the left cerebellar peduncles. The morphology and staining characteristics of the organisms within the abscess were consistent with Corynebacterium pseudotuberculosis.

Animals↗
PubMed1993

Community care. Your role or mine?

On 1 April social services departments took on lead responsibility for co-ordinating and funding community care, under the NHS and community care reforms. Cath Jackson spotlights East Sussex where health and social services managers are confident the systems are in place to implement the changes.

Community Health Nursing↗
PubMed1993

Children behind bars.

Over half the women serving prison sentences are mothers--many with dependent children under 16. Three women's prisons have special mother and baby units but there is little provision for the majority of women prisoners to maintain contact with their children. Campaigners say too little thought is given to the rights of the children.

Child↗
PubMed1993

Water. Scots verdict.

Explore the source record for details and available documents.

Community Health Nursing↗
PubMed1993

Health promotion: stepping into the breach--again.

Despite government resistance to formal merger, district and family health service authorities (DHAs and FHSAs) are increasingly looking to make joint community nurse appointments to fill evident gaps in general practitioner health promotion services. Cath Jackson highlights two pioneering projects.

Family Practice↗