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Biomedical subjects

A Jackson

Publications and source records attributed to A Jackson.

At least 343 records · Page 19Linked to original sources
PubMed1985

Teenage school refusers grow up: a follow-up study of 168 subjects, ten years on average after in-patient treatment.

Efforts were made to follow up 168 young teenage school refusers ten years, on average, after they had been treated as inpatients in an adolescent psychiatric unit. Almost half were well or much improved throughout the follow-up period. Outcome was most satisfactory in intellectually bright children treated under the age of 14 and among those who were well or substantially better shortly after discharge. Thirty per cent of the group had received treatment for psychiatric illness, 14% had seen a psychiatrist and 5% had been admitted to hospital for psychiatric treatment during the follow-up period. Thirty per cent appeared to be disturbed at the time that they were reviewed. The 'decennial-inception' and 'point-prevalence' rates for psychiatric disorder appeared unduly high by comparison with local and national rates of disturbance.

Adult↗
PubMed1985

The binding of ConA and other lectins to surface glycoproteins: a comparison of a subcutaneous tumour and its liver metastases.

The glycoprotein composition of a transplantable subcutaneous lymphosarcoma (1 degree) and its liver metastases (2 degrees) have been examined in Triton X-100 extracts obtained from tissue, single cells and membrane preparations by using electrophoresis and treatment with radio-labelled lectins. No consistent differences could be detected in the electrophoretic patterns of 1 degree and 2 degrees tumour using RCA-60 or gorse. Small differences were detected using Concanavalin A; all but one of these were eliminated as being due to differential host contamination. A minor band of 178,000 daltons molecular weight was found in 1 degree tissue, cells and membranes that was absent in extracts from 2 degrees tumour. Percoll density gradient separations suggested that this glycoprotein belonged to a small subpopulation of cells; their identity remains uncertain. The band was still detected when tumour was grown from direct liver implants, but it disappeared when this growth metastasized to another lobe. The results provide evidence that metastasis can be accompanied by a very subtle change in the tumour glycoprotein profile. Such a change may have important consequences for host/tumour interactions and subsequent metastatic spread.

Animals↗
PubMed1984

Experimental choreoathetosis produced by injection of a gamma-aminobutyric acid antagonist into the lentiform nucleus in the monkey.

An experiment is reported in which injections of the gamma-aminobutyric acid antagonist bicuculline into the lentiform nucleus of the monkey gave rise to a contralateral choreoathetoid dyskinesia. Evidence was obtained of functional heterogeneity between the dorsal and ventral lentiform nucleus, in that only injections into its ventral part gave rise to dyskinesia.

Animals↗
PubMed1984

Recurrent retching with gastric mucosal prolapse. A proposed prolapse gastropathy syndrome.

A clinical syndrome is described in 22 patients who present with epigastric pain alone or with hematemesis which is associated with a precedent history of recurrent early morning retching or postprandial retching. The characteristic endoscopic finding is a knuckle of inflamed and sometimes bleeding gastric mucosa which repeatedly prolapses into the esophageal lumen during retching. Other upper gastrointestinal lesions are not found. Retching is thought to cause the forceful prolapse and subsequent traumatization of gastric mucosa. The episodes of vigorous retching and resultant gastric trauma are now considered to be the cause of the abdominal pain and hematemesis, and it is proposed that this combination of clinical features illustrates a distinct syndrome which we have called prolapse gastropathy. This condition is a significant cause of hematemesis and abdominal pain in a group of nonalcoholic patients who demonstrate an unusual sensitivity to gag and retch.

Adult↗
PubMed1984

Differences in surface expression of WGA-binding proteins of cells from a lymphosarcoma and its liver metastases.

The protein and glycoprotein compositions of a subcutaneous lymphosarcoma (1 degree) and its metastatic deposits in the liver (2 degrees) have been investigated in Triton X-100 extracts obtained from tissue, single cells and membrane preparations. No consistent differences in the electrophoretic patterns for 1 degree and 2 degrees tissue or cells were observed for separations visualized with the protein stain Coomassie Blue. Substantial and consistent reductions in the glycoprotein content of extracts from 2 degrees tissue or cells were observed if the separated proteins were treated with the radioiodinated lectin, Wheat Germ Agglutinin (WGA). Densitometric scans of autoradiographs indicated that WGA binding occurred in 4 major areas; the approximate mol. wts of these were 180,000, 102,000, 84,000 and 23,000 daltons. All these components except the 23,000 component were shown to be located in the cell membrane and to be reduced in 2 degrees preparations. Possible sources of host contamination were also investigated, but these did not show WGA binding patterns that were similar to that obtained for the tumour. If 2 degrees tumour was transplanted into the 1 degree site, the resultant growth exhibited a WGA-binding pattern normally shown by a 1 degree tumour growing in this site. Conversely, if 1 degree tumour was transplanted into the liver, the WGA binding of the resultant growth was substantially reduced. The results suggest that local and metastatic tumours do contain cells that express different glycoproteins on their surfaces but that the site of tumour growth is a very important factor in determining this difference in surface expression.

Animals↗
PubMed1984

Experimental hemichorea/hemiballismus in the monkey. Studies on the intracerebral site of action in a drug-induced dyskinesia.

Antagonists of the neurotransmitter gamma aminobutyric acid (GABA) were injected at seventy intracerebral sites in the conscious monkey. Injections located in or near to the subthalamic nucleus provoked involuntary movements of the contralateral limbs. These movements had the characteristics of chorea and, when severe, resembled hemiballismus as seen following subthalamic nucleus lesions in man and monkey. Localized injections of GABA antagonists into the medial segment of the globus pallidus were without observable effect on motor activity. These observations are discussed with regard to the role of GABA in subthalamopallidal relations. Injection of GABA antagonists at some other sites provoked different forms of dyskinesia. Injections in or near the zona incerta adjacent to the subthalamic nucleus induced torticollis and circling behaviour either in isolation or in addition to contralateral limb dyskinesia. Injections at some sites located in the lateral segment of the globus pallidus or in the putamen induced choreoathetoid or myoclonic movements, respectively.

Animals↗
PubMed1984

The Fc receptor for IgG on human natural killer cells: phenotypic, functional, and comparative studies with monoclonal antibodies.

We compare five monoclonal antibodies ( B73 .1, 3G8 , Leu- 11a , Leu- 11b , and VEP13 ) that react with natural killer (NK) cells and polymorphonuclear cells (PMN). We show that all of these antibodies are directed against and inhibit the functional properties of the receptor for the Fc portion of IgG (FcR). Modulation of the FcR on NK cells after reaction with immune complexes induces the disappearance of the antigen(s) recognized by each of the five antibodies. Conversely, the antibodies block binding of IgG-sensitized erythrocytes to the NK cells and PMN and inhibit their ability to mediate cytotoxicity against antibody-sensitized tumor target cells. By using two-color immunofluorescence techniques, we characterize directly the lymphocyte population recognized by these antibodies and show that it is a homogeneous subset that does not bear markers of either B or T cells, with the exception of the 33,000 dalton antigen characteristic of suppressor/cytotoxic T cells present in 20 to 50% of the cells, and the 45,000 dalton receptor for sheep erythrocytes present on 80 to 90% of the cells. The phenotype of the cells reacting with the monoclonal antibodies corresponds to that of NK cells. Cross-competition experiments indicate that these antibodies detect at least two distinct epitopes on FcR, one ( B73 .1) preferentially expressed on NK cells and one or more ( 3G8 /Leu- 11a /Leu- 11b / VEP13 ) preferentially expressed on PMN. The lack of reactivity of these antibodies with B cells suggests that human B cells bear a different FcR from that on NK cells and PMN.

Antibodies, Monoclonal↗
PubMed1984

Effect of association, dissociation and positive self-talk strategies on endurance performance.

The purpose of the present investigation was to compare associative, dissociative and positive self-talk strategies in the performance of two endurance tasks. In Experiment 1, subjects (N = 40) were asked to employ one of these strategies during a 30 minute run around a quarter mile track. Subjects were instructed to run as fast and as far as they could during the allotted time. Heart rate, feelings, and cognitions were also assessed. Results indicated no significant between group differences on either performance or questionnaire measures. In Experiment 2, subjects (N = 230) were asked to employ the same cognitive strategies as described above throughout the duration of a muscular leg-endurance task. Results showed that the dissociation and positive self-task conditions produced significantly greater persistence than the association or control conditions. No significant differences were found for heart rate and other questionnaire data. The findings are discussed in terms of task type, the processing of internal and external cues and the mediating role of previous experience in affecting subjects' use of these cognitive strategies. Future directions for research are offered.

Adaptation, Psychological↗
PubMed1984

Automatic calculation for the renal failure diet.

A logical scheme for algorithm for computation of the renal failure diet is presented along with its application to a programmable calculator. The program is user-interractive; the user may add or delete foods without re-entering previous data. Program outputs include water, protein, calories, carbohydrate, sodium, potassium, calcium, phosphorus, and the essential amino acids (EAA) in absolute and percentage terms. As an index of relative protein quality, the chemical score is computed on a meal-by-meal basis. Individual EAA scores are available to permit designation of the limiting EAA of a meal. A major benefit of the program is the ability to explore and document rapidly a wide variety of meal plans. Improvements in "user-friendliness" will facilitate application with patients.

Computers↗
PubMed1983

Anatomical and electrophysiological studies on the reciprocal projections between the subthalamic nucleus and nucleus tegmenti pedunculopontinus in the rat.

Reciprocal projections between the subthalamic nucleus of the diencephalon and the brain stem nucleus tegmenti pedunculopontinus have been demonstrated and studied anatomically and electrophysiologically in the rat. Injections of the fluorescent compound Fast Blue into pedunculopontinus and the surrounding peribrachial region of the mesencephalon gave rise to retrogradely-labelled neurone cell bodies in the ipsilateral subthalamic nucleus. A minimum of 1% of subthalamic nucleus neurones appeared to contribute to this projection. Electrical stimulation of the subthalamic nucleus in chronically decorticated rats resulted in inhibition of extracellularly recorded ipsilateral pedunculopontine cells which had themselves been identified (by antidromic activation) as projecting rostrally as far as the subthalamic nucleus or entopeduncular nucleus. Injection of the enzyme horseradish peroxidase into the subthalamic nucleus resulted in retrograde labelling of neurones in the ipsilateral nucleus tegmenti pedunculopontinus with additional contralateral labelling in some animals. Similar pedunculopontine labelling was not seen after injection of horseradish peroxidase into either the zona incerta or lateral hypothalamus. Stimulation of the subthalamic nucleus gave rise to antidromic activation of some neurones in nucleus tegmenti pedunculopontinus. The rate of conduction of the pedunculopontine-subthalamic projection was estimated to be approximately 1.7 m/s. Electrical stimulation of pedunculopontinus gave rise to orthodromic activation of some subthalamic nucleus neurones which had themselves been identified (by antidromic activation) as projecting to the globus pallidus or substantia nigra. The nucleus tegmenti pedunculopontinus is in a position to fulfill two roles--to control the activity of rostrally-located motor centres such as the globus pallidus, entopeduncular nucleus, subthalamic nucleus and substantia nigra and, by reciprocal connections, to mediate in part the effects of these structures on the lower motor system. The observations presently described are a first step in the analysis of the potential role of the pedunculopontine nucleus in the modulation of activity in, and the mediation of activity from, the basal ganglia and related motor structures of the diencephalon and mesencephalon.

Animals↗
PubMed1983

Nucleus tegmenti pedunculopontinus: efferent connections with special reference to the basal ganglia, studied in the rat by anterograde and retrograde transport of horseradish peroxidase.

The efferent connections of the brain stem nucleus tegmenti pedunculopontinus were studied in the rat using the techniques of anterograde and retrograde transport of the enzyme horseradish peroxidase, laying particular emphasis on that part of pedunculopontinus which receives direct descending projections from the basal ganglia and related nuclei. In a preliminary series of experiments horseradish peroxidase was injected into either the entopeduncular nucleus or the subthalamic nucleus and, following anterograde transport of enzyme, terminal labelling was identified in nucleus tegmenti pedunculopontinus, surrounding the brachium conjunctivum in the caudal mesencephalon. In a subsequent series of experiments, horseradish peroxidase was injected into that region of nucleus tegmenti pedunculopontinus which receives entopeduncular and subthalamic efferents and its efferent projections were studied by anterograde transport of the enzyme. The results indicate that nucleus tegmenti pedunculopontinus gives rise to widely distributed efferent projections which terminate rostrally in mesencephalic, diencephalic and telencephalic structures and caudally in the pontine tegmentum. In the mesencephalon, terminal labelling was found in the pars compacta of the ipsilateral substantia nigra and sometimes in the adjoining ventral tegmental area. Labelling was also found in the ipsilateral half of the periaqueductal grey. In the diencephalon terminal labelling occurred bilaterally in the subthalamic nucleus and ipsilaterally in the intralaminar nuclei of the thalamus. Further rostrally, terminal labelling was particularly evident in the ipsilateral pallidal complex, especially in the caudal two-thirds of the entopeduncular nucleus and the ventral half of the caudal third of the globus pallidus. Caudal to pedunculopontine injection sites dense labelling was observed in the reticular formation of the pontine tegmentum. In a final series of experiments, confirmation of apparent pedunculopontine efferent projections was sought using the retrograde transport of horseradish peroxidase. Enzyme was injected into sites possibly receiving pedunculopontine efferents and the peribrachial area of the brain stem was examined for retrograde cell labelling. In this way, pedunculopontine projections were confirmed to the globus pallidus, entopeduncular nucleus, subthalamic nucleus, substantia nigra, parafascicular nucleus and pontine reticular formation. Injections into the globus pallidus or subthalamic nucleus gave rise to retrograde cell labelling bilaterally in pedunculopontinus. In addition, retrograde transport studies alone demonstrated projections from pedunculopontinus to the cerebral cortex and to the spinal cord. It is concluded that the nucleus tegmenti pedunculopontinus has reciprocal relationships with parts of the basal ganglia and some functionally related nuclei (in particular, the pallidal complex, subthalamic nucleus and substantia nigra).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗