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Biomedical subjects

M Wright

Publications and source records attributed to M Wright.

At least 271 records · Page 15Linked to original sources
PubMed1981

Physiologic and analgesic effects of acupuncture in the dog.

Two acupuncture regimens were compared as to their efficacy in inducing analgesia sufficient for midline abdominal incisions in dogs. In addition, the physiologic effects of electrostimulation of the single point that the 2 regimens had in common, Tsu-san-li (stomach or St-36), were examined. The physiologic effects were compared with those monitored during the procedure used for induction of analgesia. Electrostimulation of 1 acupoint combination, St-36 and Yang-ling-chuan (gallbladder or GB-34), induced effective analgesia for an abdominal midline incision in 8 of 9 dogs tested (89%). The second point combination, St-36 and San-yin-chiao (spleen or Sp-6), induced effective analgesia for an abdominal midline incision in only 2 of 8 dogs tested (25%). Analgesia was inferred when an animal's struggling response during the incision procedure was absent or minimal. Heart rate, respiratory rate, and arterial blood pressure were monitored during acupoint stimulation. Significant changes in heart rate or respiratory rate were not detected during electrostimulation of St-36, St-36 and GB-34, or randomly selected nonacupuncture metatarsal loci. Although there were statistically significant decreases in systolic blood pressure during electrostimulation of nonacupuncture points alone and of St-36 alone, the magnitude of these increases was small, ranging from 3.75 mm of Hg to 4 mm of Hg.

Abdomen↗
PubMed1981

Age-related facilitation in recall following semantic processing.

The present experiment was an attempt to reduce or eliminate the age-related deficit in recall following a semantic processing task. It was hypothesized that variables that might affect depth or elaborateness of semantic processing would consequently affect the size and direction of recall differences between younger and older adults. Specifically, we tested for the effects of differential word familiarity and one vs two semantic tasks on recall in young and older adults following semantic processing. The results demonstrated that word familiarity and number of processing tasks both had a strong effect on recall. Older adults benefited as much from additional semantic processing as younger adults. Additionally, older adults actually showed higher recall than younger adults when subjects processed words more familiar to older adults. These results demonstrate that, given appropriate conditions, older adults may actually show higher performance in a memory task than younger adults.

Adolescent↗
PubMed1981

Regulation of mitosis onset and thymidine kinase synthesis during the cell cycle of Physarum polycephalum: action of aphidicolin.

In Physarum polycephalum (Myxomycetes) aphidicolin has been found to delay metaphase onset when applied to synchronous plasmodia 3 h before control metaphase. In contrast to the action of temperature shifts, aphidicolin treatment did not delay the initiation of the increase of thymidine kinase synthesis (EC 2.7.1.21, ATP-thymidine 5' phosphotransferase) and the decrease of the synthesis of thymidine kinase occurred normally after completion of mitosis in presence of aphidicolin. The amount of thymidine kinase synthesized was larger for aphidicolin treated plasmodia than in the control due to both a longer period of increased synthesis and a higher maximum rate of synthesis. These results were interpreted by postulating the presence of two regulatory pathways. The first one acting on the increase of the synthesis of thymidine kinase and on mitosis onset was sensitive to temperature shifts from 22 to 32 degrees C. The second one acting on mitosis onset only was sensitive to aphidicolin.

Aphidicolin↗
PubMed1981

Regulation of thymidine kinase synthesis during the cell cycle of Physarum polycephalum: the effects of two microtubule inhibitors.

Methyl benzimidazole carbamate and griseofulvin are two microtubule inhibitors which perturb plasmodial mitosis in Physarum polycephalum. These two compounds perturb not only the mitotic process leading to abortive mitosis but delay the onset of mitosis. Both drugs delayed the onset of thymidine kinase synthesis (EC 2.7.1.21, ATP: thymidine 5'phosphotransferase) which occurred concomitantly with mitosis. Thus, thymidine kinase synthesis, a cell cycle event which is not thought to have any relationship with the microtubular system, was perturbed in the same way as mitosis in the presence of two chemically unrelated microtubule inhibitors. It is suggested that the microtubular system is an essential part of a regulatory pathway of the cell cycle which plays a role in at least two events of the cell cycle: the onset of thymidine kinase synthesis, and the onset of mitosis.

Benzimidazoles↗
PubMed1979

Computed tomography of infratentorial masses in children.

Seventeen cases of infratentorial mass lesions (excluding abscesses) in children are reviewed. The findings after computed axial tomography (CAT) are described, as well as the changes that were revealed by plain radiographs of the skull. Ancillary investigations were performed in 11 cases, and their usefulness is assessed. The possibility of making a provisional diagnosis of the nature of the lesion based on CAT findings is discussed.

Astrocytoma↗
PubMed1979

Physarum thymidine kinase. A step or a peak enzyme depending upon temperature of growth.

The variations of thymidine kinase or ATP:thymidine 5'-phosphotransferase (EC 2.7.1.21) during the cell cycle of Physarum polycephalum plasmodia have been studied at two extreme physiological temperatures: 22 degrees C and 32 degrees C. At 22 degrees C the enzyme activity increases near mitosis and stays constant during late S and G2 phases, exhibiting the typical pattern of a 'step enzyme'. But at 32 degrees C thymidine kinase activity goes through a maximum 1 h 30 min after mitosis and decreases during the subsequent phases as expected for a 'peak enzyme'. The rate of enzyme degradation and/or inactivation, measured in the presence of metabolic poisons (cycloheximide or dinitrophenol), appears to follow a simple exponential function with a half-life of approximately 3 h and 1 h at 22 degrees C and 32 degrees C respectively. The effect of growth temperature on the decrease of thymidine kinase activity can account entirely for the differences in the pattern of enzyme activity at the two extreme temperatures. Tentative calculations indicate that the rate of enzyme synthesis is nearly constant during the cell cycle except near mitosis, where it is temporarily increased. The results suggest the existence of a regulatory mechanism able to modulate the rate of synthesis of thymidine kinase during the cell cycle.

Cycloheximide↗
PubMed1979

Reversible hypertension due to carcinoma of the ureter.

A patient who presented with hypertension of recent onset was found to have unilateral hydronephrosis. Increased activity of the renin-angiotensin system was documented with renal-vein-renin concentrations. The hydronephrosis was due to a primary transitional cell carcinoma of the ureter. Following nephroureterectomy, blood pressure returned to normal and has remained so for two years.

Blood Urea Nitrogen↗
PubMed1977

Gravity-induced cell elongation.

When the flowering stalks of grasses are displaced from the vertical position they are caused to bend at special gravity perceptive regions, the nodes. Growth of the lower side of the node returns the shoot to its original orientation with respect to gravity, but when this is achieved, growth ceases. Possible mechanisms by which elongation growth is turned on in the lower sides and turned off again once the stalk is vertical are described. The facilities of Spacelab offer a unique opportunity for testing models of gravity perception and response.

Dose-Response Relationship, Drug↗
PubMed1977

Synthesis of a 125I-labelled derivative of the antibiotic griseofulvin.

A derivative of griseofulvin has been synthesised, in which the 2'-O-methyl group is replaced by a 2'-(2-iodoethoxy), 125I-labelled group. This derivative is at least as potent as griseofulvin itself, when assayed for inhibition of growth on the Myxomycete Physarum polycephalum.

Griseofulvin↗
PubMed1976

[Demonstration of the action of methyl benzimidazole 2 yl carbamate (MCB) and methyl(5(2 thienyl carbonyl) 1 H benzimidazole 2 yl carbamate) (R17934) on the nucleus of Physarum polycephalum (Myxomycetes)].

The toxicity of these compounds was determined in the amoebae and plasmodia. An electron microscopic study shows an increase in nuclear size which is in agreement with the increase of the total amount of DNA. Microtubules are present but they are not organized in a normal mitotic apparatus. Some other nuclear abnormalities are described.

Benzimidazoles↗