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Biomedical subjects

R Thompson

Publications and source records attributed to R Thompson.

At least 289 records · Page 16Linked to original sources
PubMed1984

Visual evoked potentials in the diagnosis of multiple sclerosis.

A three-year collaborative study was done on 96 patients presenting with signs of neurological dysfunction suggestive of multiple sclerosis. All were tested using Visual Evoked Potentials, with the final diagnosis not known to the tester. Patients with bilateral Visual Evoked Potential P1 wave conduction delays were more likely to have a subsequent diagnosis of MS, than those with unilateral delays, or normal VEPs. The average delay between the onset of the first symptom, and a definitive diagnosis of MS was 3.5 years. The most frequent initial symptom was paresthesias of the lower extremities, followed by blurred vision. This study suggests that the presence of Visual Evoked Potential abnormalities may be useful in the longitudinal diagnostic evaluation of patients with a presumptive diagnosis of multiple sclerosis.

Adult↗
PubMed1984

Visual evoked potentials and ibuprofen (Motrin) toxicity.

A patient taking ibuprofen (Motrin) for the relief of osteoarthritis developed, after two months, decreased visual acuity and decreased color vision. Initially the Visual Evoked Potentials, showed decreased wave amplitudes, and increased conduction times in both eyes. After stopping the drug, the Visual Evoked Potentials returned to normal one month before the visual acuity improved. We feel that Visual Evoked Potentials are useful for screening patients on ibuprofen, and prognosticating their recovery, when a secondary toxic optic neuritis develops.

Aged↗
PubMed1984

Visual evoked potentials as an aid in the diagnosis and treatment of temporal arteritis.

A patient who presented with temporal arteritis was followed using pattern visual evoked potentials (VEPs). Prior to treatment, both amplitudes and wave latencies of the VEP were abnormal. Following a two-week course of corticosteroids, both the visual acuity and VEPs returned to normal. It is suggested by this patient, that VEPs may be useful in the diagnosis and management of patients with temporal arteritis.

Aged↗
PubMed1983

The control region of the F plasmid transfer operon: DNA sequence of the traJ and traY genes and characterisation of the traY leads to Z promoter.

The complete nucleotide sequence of the F plasmid transfer genes traJ and traY, together with the promoter-proximal region of the traA gene has been determined. The traJ reading frame has been confirmed by sequencing the traJ90 amber mutant allele. The predicted amino acid sequence of the TraJ protein shows that this outer-membrane protein lacks a signal sequence. The pattern of codon usage within the traJ gene is different from that of genes for abundant outer-membrane proteins and is closer to that of genes that are expressed at relatively low levels. We have located the traY leads to Z operon promoter by in vitro run-off transcription experiments and have developed in vivo assays for the activity of the promoter by fusing it to galactokinase and kanamycin-resistance genes.

Bacterial Proteins↗
PubMed1983

Brain systems and long-term memory.

This paper focuses mainly on those findings derived from lesion studies on the rat which help to identify ensembles of neural structures concerned with the expression of previously learned responses. At the outset, the use of the lesion method in the search for those neurological circuits underlying memory is defended. This is followed by an evaluation of neocortical and subcortical systems in long-term memory. Subsequently, a modest list of tentative functional neural "complexes" involved in the maintenance of certain classes of learned responses is given, based largely upon the author's own research. It is concluded that the key to the understanding of the neurological substrates of long-term memory lies in the identification of those subcortical sites which interact with neocortical sites in the performance of complex learned tasks. The most likely subcortical sites involved in this interaction appear to inhabit the regions of the basal ganglia, limbic midbrain area, and ventral portions of the brainstem reticular formation.

Animals↗
PubMed1983

Dose-response study with ibuprofen in rheumatoid arthritis: clinical and pharmacokinetic findings.

Clinical response and plasma pharmacokinetics were studied in 20 rheumatoid patients receiving three dosages of ibuprofen. There was a significant response to 1600 mg daily of ibuprofen by all three clinical measurements but increasing the daily dosage to 2400 mg produced no overall increase in response. The AUC increased with increasing daily drug dosages from 800 to 2400 mg daily and the dose normalised AUC fell by 15% over the same dosage range. The fraction of ibuprofen not bound to plasma proteins increased with increasing dosage and may contribute to the fall in the dose normalised AUC. There was a considerably inter-individual variation in the AUC. There was no significant correlation between AUC and clinical response as measured by articular index and there was a weakly significant correlation between AUC and clinical response as measured by a visual analogue pain index. Pharmacokinetic variables probably account for only a small part of the inter-individual variation in response of rheumatoid patients treated with increasing dosages of the non-steroidal, anti-inflammatory drug ibuprofen.

Adult↗
PubMed1983

Increased bone metabolism in rheumatoid arthritis as measured by the whole-body retention of 99Tcm methylene diphosphonate.

Bone metabolism in 21 patients with rheumatoid disease was investigated by measurement of the 24-hour whole body retention (WBR) of 99Tcm methylene diphosphonate (MDP) in parallel with clinical, radiological, and biochemical measurements (urinary excretion of hydroxyproline) of disease activity. Corticosteroid-treated patients of those with other forms of metabolic bone disease were excluded from the study. WBR was increased in the rheumatoid patients as compared with 21 age- and sex-matched controls (p less than 0.05), and there was a significant correlation in the rheumatoid group between WBR and urinary excretion of hydroxyproline (p less than 0.01) and between urinary excretion of hydroxyproline and an articular index (p less than 0.05) and global index (p less than 0.01) of disease activity. The increased WBR of the rheumatoid patients was not explicable by factors such as immobilisation, and the results are interpreted as reflecting an overall increase in bone metabolism which may occur in rheumatoid arthritis as part of the disease process.

Adult↗
PubMed1983

Life events precipitating mania.

A study of 20 manic patients, with patient and matched control comparisons, showed a two fold increase in life events during the 4 month period before admission to hospital. Life events, independent of affective illness and having significant objective negative impact (i.e. traumatic) were significantly more common. These findings are considered in relation to social relationships, family history of affective illness and the use of psychotropic medication.

Adult↗
PubMed1983

Depression in chronic schizophrenia.

Eighteen depressed chronic schizophrenic out-patients were matched with non-depressed schizophrenic out-patients. The depressed schizophrenics had had significantly more psychiatric admissions, past depression, past treatment for depression, significantly more had attempted suicide, lived alone, had low self-esteem, had early parental loss and had had more life events in the six months before the onset of depression. Depressive disorder in schizophrenic out-patients well controlled by neuroleptics may occur in those who are at risk for depression and experience an excess of life events.

Adult↗
PubMed1983

Visual versus computerised assessment of left ventricular function from cinéangiography.

Visual assessment of left ventricular function from cinéangiography was compared with computerised assessment in 48 randomly selected cinéangiograms. The parameters compared included end-diastolic volume, end-systolic volume, stroke volume, ejection fraction and left ventricular output. There was poor agreement between visual and calculated values for end-diastolic volume, stroke volume and left ventricular output, but good agreement for ejection fraction and moderately good agreement for end-systolic volumes. Absolute values are particularly difficult to assess.

Cardiac Output↗
PubMed1983

Effects of dibutyryl cyclic adenosine 3':5'-monophosphate on the growth of cultured human small-cell lung carcinoma and the specific cellular activity of L-dopa decarboxylase.

High activity of L-dopa decarboxylase separates small (oat)-cell from non-small-cell lung cancer in cell culture. The present study investigates relationships between the specific cellular activity of this enzyme and: (a) cell growth kinetics of an established line (O-H-1) of human small cell lung carcinoma, and (b) responses of these cells to treatment with cyclic adenosine 3':5'-monophosphate and sodium butyrate. The O-H-1 cells, as for most other established small-cell lines, grow as suspended cell aggregates. During growth, the specific cellular activity of L-dopa decarboxylase parallels levels for [3H]thymidine labeling index and the ratio of cells in G2-M to those in G1-G0 phases of the cell cycle. Each of these parameters is 2- to 3-fold higher during exponential versus stationary growth. Continuous treatment with dibutyryl cyclic adenosine 3':5'-monophosphate (dcAMP; 0.1 or 1 mM) and 1 mM theophylline produces simultaneous cessation of cell growth and an increase in cellular L-dopa decarboxylase activity. During this period, analyses of DNA histograms reveal an increase in the number of cells in the G2-M phase; the rate of increase in the ratio of G2-M to G1-Go cells paralleled the rate of increase in specific activity of the enzyme. The effects of the dcAMP were promptly reversible; release of the apparent G2-M block preceded regrowth of the cells and was accompanied by a return of L-dopa decarboxylase activity to base-line levels. The changes in enzyme activity were specific for cyclic adenosine 3':5'-monophosphate; another cyclic adenosine 3':5'-monophosphate analogue, 8-bromo adenosine cyclic 3':5'-monophosphate yielded similar increases in L-dopa decarboxylase to those seen with dcAMP, while 0.01 to 1 mM butyrate alone produced the inhibition of cell growth but no changes in specific activity of L-dopa decarboxylase or percentage of cells in the different phases of the cell cycle. We conclude that the specific activity of L-dopa decarboxylase, a key neuroendocrine marker for cultured small-cell lung carcinoma, is highest during proliferative growth and/or when these cells are in the G2M phase of the cell cycle. The differential effects of dcAMP and sodium butyrate offer potential for exploring neuroendocrine differentiation in this important lung cancer and related endocrine neoplasms.

Aromatic-L-Amino-Acid Decarboxylases↗
PubMed1983

In vitro and in vivo growth characteristics of two different cell populations in an established line of human neuroblastoma.

Two distinct cell morphologies were appreciated and separated in a long-established culture line (CHP-100) of human neuroblastoma. Both cell types carried chromosomal markers characteristic of neuroblastoma cells and the parent line; in addition, separate karyotypic changes in each cell type established them as separate and enriched populations. A small, refractile cell, designated CHP-100-S, was present and formed numerous cytoplasmic processes. A distinctly larger cell, CHP-100-L, was less refractile and lacked processes. The two cell types exhibited marked differences in adhesive properties in vitro. CHP-100-L adhered tightly to the culture flask and required enzymatic treatment for removal; CHP-100-S adhered loosely and could be harvested into the medium by simply tapping the flask. These two harvesting procedures were used to obtain highly enriched populations of each cell type, both of which proved to be tumorigenic in the nude mouse. In vitro, no significant difference in growth rates was observed between CHP-100-S (doubling time, 26 hr) and CHP-100-L (21 hr). However, in the nude mice, following inoculation of equal cell numbers, CHP-100-L cells grew much larger tumors than did CHP-100-S cells (3- to 100-fold increases over 25 days). Local invasion was also noted more frequently with the CHP-100-L explants. Reculturing of the mouse explants showed that the distinct cell morphologies were maintained even after multiple passages. The presence of heterogeneous cell populations in single tumors is of much potential importance for the clinical and biological behavior of neoplasms. The present data establish cultured human neuroblastomas as one model for studies of cell heterogeneity and suggest potentially important ramifications for the different cell types observed in the growth patterns of this neoplasm.

Animals↗
PubMed1982

Promoter mapping and DNA sequencing of the F plasmid transfer genes traM and traJ.

The nucleotide sequence of the DNA encoding the traM, finP and the promoter proximal segment of the traJ gene of the F plasmid has been determined. The predicted amino acid sequence for the traM protein shows that this inner membrane protein contains no signal sequence. The promoters for both the traM and traJ genes have been mapped by in vitro transcription and nuclease S1 protection experiments. No unambiguous location can be assigned to the finP gene but all candidates, if translated, would encode small proteins of between 24 and 52 amino acids.

Amino Acid Sequence↗