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Biomedical subjects

N J Dodd

Publications and source records attributed to N J Dodd.

67 records · Page 4Linked to original sources
PubMed1975

Electron spin resonance study of changes during the development of a mouse myeloid leukaemia. II. The ascorbyl radical.

The ascorbyl radical concentration has been observed, by means of electron spin resonance spectroscopy, in the blood, spleen and liver of RF/J female mice throughout the development of a myeloid leukaemia. Changes in the concentration of the radical were detectable from an early stage in the disease and did not appear to be directly due to the leukaemic cells but could possibly be due to a reaction against them. Changes in the concentration of the paramagnetic metal ions during the leukaemia have been reported previously and it was found that changes in some of these species correlated with changes in the ascorbyl radical concentration.

Animals↗
PubMed1975

Effects of ionizing radiation on dried spores of Osmunda regalis III. 35 GHz e.s.r. study.

The use of 35 GHz microwave frequency has greatly simplified the separation of overlapping signals in dried irradiated fern spores. While in general confirming the conclusions previously drawn from X-band spectra, the use of Q-band has clarified several assignments of radical groups and allowed the recognition of additional radical groups or sub-groups.

Electron Spin Resonance Spectroscopy↗
PubMed1975

Effects of ionizing radiation on dried spores of Osmunda regalis III. 35 GHz e.s.r. study.

The use of 35 GHz microwave frequency has greatly simplified the separation of overlapping signals in dried irradiated fern spores. While in general confirming the conclusions previously drawn from X-band spectra, the use of Q-band has clarified several assignments of radical groups and allowed the recognition of additional radical groups or sub-groups.

Electron Spin Resonance Spectroscopy↗
PubMed1973

Some EPR signals in tumour tissue.

Normal and tumour tissues from rats, blood from normal and tumour bearing rats, and normal human blood were examined using the electron paramagnetic resonance (epr) technique. At low temperature a triplet epr signal, which is known to be produced by a NO-haemoprotein complex, was detected in some tumour samples and in decaying normal liver. At room temperature all of the tumour samples examined gave a doublet signal. This signal was also detected in blood but not in other normal tissues. The signal has a g value of 2·0054 ± 0·0002 and a hyperfine splitting of 1·80 ± 0·05 G and is assigned to the ascorbyl free radical. Model experiments suggest that the appearance of detectable concentrations of this radical result from a disturbance of the normal state of the ascorbic acid, dehydroascorbic acid redox system. It was verified that cell division is not responsible for the ascorbyl radical although autolysis may be involved. A possible relationship between the formation of ascorbyl radicals and other paramagnetic species in tumours is discussed.

Animals↗
PubMedDate not supplied

Use of ESR for the detection of irradiated dates (Phoenix dactylifera L.).

One variety (Aple) of Libyan dry dates (Phoenix dactylifera L.) was irradiated in a 60Co source to absorbed doses of 0.8, 1.0, 1.5 and 2.0 kGy. Unirradiated date stone contains a radical with a single line g = 2.0045, feature A. Irradiation to a dose of 2.0 kGy (the recommended dose for fruits in U.K.) induces the formation of additional radicals with signals g = 1.9895 and 2.0159, feature C. The single line having g = 2.0045 decays in both unirradiated and irradiated samples whereas the additional signals g = 1.9895 and 2.0159 remain almost unchanged over a period of time 15 months stored at room temperature and 4 degrees C.

Electron Spin Resonance Spectroscopy↗
PubMedDate not supplied

Synthesis and electron spin resonance study of spin-labelled compounds related to tumour-growth inhibitory nitroarylaziridines.

Three stable free radicals have been prepared which are akin to 5-aziridino-2,4-dinitrobenzamide (CB 1954); these compounds all contain a nitroxide function. The metabolism and excretion of two such compounds in mice has been monitored by electron spin resonance (ESR) spectroscopy and compared with that of the simpler nitroxide, 4-keto-2,2,6,6-tetramethylpiperidino-1-oxyl (tempone).

Animals↗
PubMedDate not supplied

An ESR spin label study of childhood kidney tumours.

The isolated membranes of cells from normal kidneys, foetal kidneys, Wilms' tumours, and bone-metastasizing renal tumours of childhood (BMRTC) have been examined by electron spin resonance, using the lipophilic spin label 5-doxyl stearic acid. No differences in membrane rigidity were detected between normal kidney cells and Wilms' tumour cells, over the temperature range 5 to 40 degrees C. The membranes of foetal kidney cells showed no significant difference at physiological temperatures, but were more rigid than the membranes of normal kidney cells at lower temperatures. In contrast, BMRTC cells showed lower membrane rigidity than normal kidney cells at all temperatures studied, BMRTC cells, unlike normal kidney and Wilms' tumour cells, lack surface fibronectin, but addition of fibronectin to BMRTC cell membranes, in suspension, had no detectable effect on their rigidity.

Cell Membrane↗