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Biomedical subjects

G Campbell

Publications and source records attributed to G Campbell.

At least 91 records · Page 5Linked to original sources
PubMed1995

The Nithsdale Schizophrenia Surveys. XIV: Plasma lipid peroxide and serum vitamin E levels in patients with and without tardive dyskinesia, and in normal subjects.

BACKGROUND: Tardive dyskinesia (TD) may be mediated through free radical damage to neurons. Plasma lipid peroxide levels are a measure of radical damage to fats. Vitamin E is a free radical scavenger. METHOD: One hundred and twenty-eight schizophrenic patients were examined for TD using the Abnormal Involuntary Movements Scale. Blood samples were taken to measure plasma lipid peroxide, serum vitamin E and cholesterol, and vitamin E:cholesterol ratios. Twenty-four patients were also examined in October 1993, January 1994, and April 1994. Biochemical results were compared in 81 patients and 79 normal subjects. RESULTS: Patients with and without TD did not differ in median plasma lipid peroxide and serum vitamin E levels, or vitamin E:cholesterol ratios. Correlations between seasonal change scores in TD and biochemical measurements were low. Lipid peroxide levels were higher and vitamin E:cholesterol ratios lower in patients than in normal subjects. Vitamin E levels were lowest in in-patients and in those living in supported accommodation. CONCLUSIONS: The results do not support the hypothesis that TD is mediated through free radical damage to neurons, but suggest increased free radical activity in schizophrenia.

Adult↗
PubMed1995

Brain regional distribution pattern of metabolite signal intensities in young adults by proton magnetic resonance spectroscopic imaging.

Proton magnetic resonance spectroscopy (1H-MRS) is evolving from single-volume localized acquisitions to multiple-volume acquisitions using magnetic resonance spectroscopic imaging (1H-MRSI). The normal regional patterns of 1H-MRSI-detectable metabolite signal intensities have yet to be established. We studied 13 healthy young adults with a multiple-section 1H-MRSI technique. The metabolite signals measured were N-acetylaspartate (NA), choline-containing compounds (CHO), creatine-phosphocreatine (CRE), and lactate. Ten neuroanatomic regions (nine bilateral) were identified in gray matter, white matter, and basal nuclei. Analysis of the data led to the following conclusions: (1) NA and CHO signals from centrum semiovale (CSO) can be used as a normalizing factor to reduce intersubject variability due to external causes; (2) in normal human brain, there is no left versus right asymmetry in the regions studied; (3) statistically significant patterns of signal distribution of NA, CHO, and CRE can be identified in normal human brain; and (4) CSO-normalized metabolite signal intensities and metabolite ratios complement each other for the detection of significant regional differences.

Adult↗
PubMed1995

Scottish neonatal intensive care units; a study of staff and parental attitudes.

The study takes a three stage approach to review Scottish unit policies, staff views and parents experiences of visiting and involvement with their low birthweight infant (1,750 gm or less) in a sample of Scottish neonatal intensive care units (NICUs). The study indicated that while most units had 'liberal' views regarding parental and family visiting some staff views were not in line with their unit policy and retained reservations about family visiting. Many parents reported visiting daily despite considerable 'social' and real costs. Unit differences emerged regarding the degree of parental involvement as measured by tasks carried out.

Adult↗
PubMed1995

Regenerative and other responses to injury in the retinal stump of the optic nerve in adult albino rats: transection of the intracranial optic nerve.

The response to injury of the proximal (retinal) stump of the intracranially transected optic nerve in adult rats has been studied by electron microscopy. The central part of the retinal stump of the optic nerve underwent severe ischaemic damage resulting in the formation by 3 days postoperation (dpo) of a cone-shaped region of necrotic tissue which extended from a base occupying most of the cross-sectional area of the nerve at the cut end to an apex within the intraorbital part of the nerve and only 2-3 mm from the eyeball. A mixture of apparently viable and dead or dying cells and axons was present in an intermediate zone surrounding the ischaemic core. Apparently intact nerve fibres occupied most of the periphery of the optic nerve. Small bundles of sprout-like axons were seen in the intermediate zone at 3 dpo, and by 5 dpo such sprouts were present at the periphery of the degenerative core. By 7 dpo, the sprouts were also found in the centre of the degenerative core, accompanied by astrocyte processes. The number of axonal sprouts present in the degenerative core and intermediate zone was much higher at 2 and 4 wk postoperation (wpo) than at 7 dpo, then declined gradually by 6 and 8 wpo. These results show that intracranial transection of the rat optic nerve produces extensive degeneration in the proximal stump and effectively produces an intraorbital axotomy of many retinal ganglion cells. Nevertheless, surviving axons display the ability to produce regenerative sprouts which persist for considerably longer than those produced after intraorbital injury.

Animals↗
PubMed1995

The effects of a lesion or a peripheral nerve graft on GAP-43 upregulation in the adult rat brain: an in situ hybridization and immunocytochemical study.

We have sought to determine (1) if thalamic neurons upregulate the growth associated protein GAP-43 as a response to injury, or if a peripheral nerve graft is required to induce, enhance or sustain such a response, and (2) if thalamic neurons with different regenerative potentials also display different GAP-43 responses. Levels of GAP-43 protein (detected by LM and EM immunohistochemistry) and of GAP-43 mRNA (detected by in situ hybridization) were compared in the thalamus of adult rats between 1 d and 180 d after making a stab lesion or after implanting a peripheral nerve autograft. Stab injury is a sufficient stimulus to cause a transient upregulation in GAP-43 expression by neurons in the thalamus (both around the graft tip and in particular in the thalamic reticular nucleus) in the first week after injury but this response is both prolonged, and enhanced in the presence of a peripheral nerve graft. In addition, we demonstrate directly, by double labelling, that neurons of the thalamic reticular nucleus displaying high levels of the mRNA for GAP-43, have axons regenerating in the distal portion of the graft. These findings lend direct support to the hypothesis that upregulation of the GAP-43 gene is essential for prolonged regenerative axonal growth. We also demonstrate GAP-43 protein in graft Schwann cells and in brain astrocytes close to the site of graft implantation.

Animals↗
PubMed1994

Nitric oxide formation is involved in vagal inhibition of the stomach of the trout (Salmo gairdneri).

Stimulation of the vagus nerves to isolated stomach preparations from trout (Salmo gairdneri) caused both excitation and inhibition of smooth muscle activity. Excitatory responses were partly reduced by atropine, suggesting that cholinergic neurons are involved. The atropine-resistant excitation could not readily be ascribed to a 'rebound' from preceding inhibition, to the production of prostaglandins, or to the activation of either adrenergic or capsaicin-sensitive fibres. Inhibitory responses were reduced by the nicotinic antagonist d-tubocurarine and more profoundly reduced by an inhibitor of nitric oxide synthase, NG-nitro-L-arginine. The latter effect was reversed by excess L-arginine. The nitric oxide donors sodium nitroprusside and nitroglycerine caused inhibition of the muscle. It is concluded that the vagal inhibitory postganglionic neurons are nitergic in this tissue.

Amino Acid Oxidoreductases↗
PubMed1994

Targeting of c-myc and beta-globin coding sequences to cytoskeletal-bound polysomes by c-myc 3' untranslated region.

The influence of the 3' untranslated region on mRNA localization was investigated by measuring the distribution of myc, beta-globin and hybrid myc-globin mRNAs between free, cytoskeletal-bound and membrane-bound polysomes in cells transfected with either control or chimeric gene constructs. c-myc sequences and beta-globin-coding sequences linked to the myc 3' untranslated region were present at greatest enrichment in cytoskeletal-bound polysomes. beta-Globin mRNA and myc-coding sequences linked to the beta-globin 3' untranslated region were recovered largely in the free polysomes. In situ hybridization confirmed that replacement of the c-myc 3' untranslated region by that of globin caused a relocalization of the mRNA. The results suggest that mRNA localization in differentiated eukaryotic cells depends on a mechanism that involves directional information in the 3' untranslated region of mRNAs.

Animals↗
PubMed1994

The distribution and colocalization of neuropeptides and catecholamines in nerves supplying the gall bladder of the toad, Bufo marinus.

The indirect immunofluorescence technique was used to determine the distribution of peptide-containing axons in the gall bladder of the cane toad, Bufo marinus. In addition, the adrenergic innervation of the gall bladder was examined by use of immunoreactivity to the catecholamine-synthesizing enzyme, tyrosine hydroxylase, and glyoxylic acid-induced fluorescence. On the basis of peptide coexistence, two intrinsic populations of neurones and their projecting fibres could be distinguished substance P neurones and vasoactive intestine peptide neurones. Neither of these two types of neurones contained any other colocalized neuropeptides. Four populations of nerve fibres arising from cell bodies outside the gall bladder were identified: nerves containing colocalized galanin, somatostatin and vasoactive intestinal peptide; nerves containing colocalized calcitonin gene-related peptide and substance P; adrenergic nerves containing neuropeptide Y; and nerves containing only adrenaline.

Animals↗
PubMed1994

The distribution and colocalization of neuropeptides in fish cardiac neurons.

Most if not all intracardiac nerve cell bodies in four species of teleost fish and a primitive air breathing fish contained immunoreactivity (IR) to vasoactive intestinal peptide (VIP). Intracardiac nerve cell bodies contained no other neuropeptide although galanin (GAL)-, substance P (SP)- and calcitonin gene-related peptide (CGRP)-IR were detected in cardiac axons. Varicose VIP-IR axons were observed in close association to the cardiac muscle in the sinus venosus and atrium, but not in the ventricle. Slightly less than half the total number of VIP-IR axons also contained colocalised GAL-IR. A smaller number of varicose axons containing colocalised SP- and CGRP-IR were also present in the sinus venous and atrium. In addition, a subpopulation of CGRP-IR axons present in the sinus venosus and atrium did not contain SP-IR. SP-IR axons lacking CGRP-IR formed boutons around the axon hillock and soma of the majority of VIP-IR nerve cell bodies. Associated with a small number of VIP/-ganglion cells were VIP/- boutons. No neuropeptides were observed in the ventricle of any species of fish studied here. These results suggest that a VIP-like peptide is localised in the cholinergic postganglionic parasympathetic neurons. Associated with some of these neurons are nerve boutons containing either SP alone or VIP alone. In addition, the fish heart is innervated by extrinsic nerve fibres containing: GAL/VIP; CGRP alone; and CGRP/SP.

Animals↗
PubMed1994

A new assay for the invasive adenylate cyclase toxin of Bordetella pertussis based on its morphological effects on the fibronectin-stimulated spreading of BHK21 cells.

When baby hamster kidney (BHK) cells are allowed to spread on fibronectin-coated substrata in the absence of serum and the presence of agents which elevate intracellular 3':5'-cyclic AMP (cAMP) levels they adopt an abnormal, stellated morphology. To determine whether the invasive adenylate cyclase (AC) toxin of Bordetella pertussis induced the same response, cell extracts were prepared from several B. pertussis strains. They were characterized for AC toxin production by enzymic assay and by immunoblotting with an AC-toxin-specific monoclonal antibody. Extracts of strains producing AC toxin induced elevated levels of intracellular cAMP in BHK cells and promoted a stellation response during cell spreading. Extracts prepared from strains defective in AC toxin production showed no effect. Using image analysis to quantify the morphological change, we have demonstrated that the effect of AC toxin on cell spreading is dose dependent. This technique is a rapid and sensitive assay for the invasive AC toxin.

Adenylate Cyclase Toxin↗
PubMed1994

Antithrombotic therapy prescribed for patients with non-rheumatic atrial fibrillation.

Patients with non-rheumatic atrial fibrillation have a fivefold increased risk of stroke. Warfarin reduces this risk by approximately two thirds, but evidence for benefit from aspirin is less compelling. We assessed whether our current practice reflects the message of the trials. In a retrospective case record study we reviewed notes of 131 patients with atrial fibrillation (AF), mean age 79 (range 53-95) years, admitted to a medical unit (72) or geriatric assessment unit (59). Thirty-two patients had paroxysmal AF. Of 115 patients with nonrheumatic AF, 36 (31%) had one or more recorded contraindication to anti-coagulation. Although 79 patients (69%) had no recorded contraindication to warfarin, only 2 took warfarin and 15 aspirin prior to admission. Ten patients commenced warfarin and 8 aspirin before discharge. Thirty-nine patients (53%) without contraindication, were discharged without antithrombotic therapy. Despite evidence to support anticoagulating patients with non-rheumatic AF, this rarely occurs.

Aged↗
PubMed1994

RK2, a glial-specific homeodomain protein required for embryonic nerve cord condensation and viability in Drosophila.

We report the identification of RK2, a glial-specific homeodomain protein. RK2 is localized to the nucleus of virtually all embryonic and imaginal glial cells, with the exception of midline glia. Embryos mutant for the gene encoding RK2 are embryonic lethal but normal for early gliogenesis (birth, initial divisions and migration of glia) and axonogenesis (neuronal pathfinding and fasciculation). However, later in development, there are significantly fewer longitudinal glia that are spatially disorganized; in addition, there is a slight disorganization of axon fascicles and a defective nerve cord condensation. This suggests that RK2 is not required for early glial determination, but rather for aspects of glial differentiation or function that are required for embryonic viability.

Amino Acid Sequence↗