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Biomedical subjects

J R Mallard

Publications and source records attributed to J R Mallard.

At least 55 records · Page 3Linked to original sources
PubMed1979

Changes in NMR relaxation times of adjacent muscle after implantation of malignant and normal tissue.

In separate experiments, normal foreign tissue and malignant tumour were implanted s.c. into the rat thigh. NMR T1 values of the adjacent normal muscle, resulting from local inflammatory reactions or from malignant invasion, were measured. Elevations in T1 of the underlying muscle occurred within 24 h in both experiments, and it is believed these were caused by rapid inflammatory and immunological reactions to the implants. However the T1 values of muscle samples adjacent to the non-malignant implants decreased during the 11 days after implantation, dropping to values within the normal range. In the second experiment there was progressive malignant invasion into the normal adjacent tissue and the elevated T1 values were maintained throughout the 12-day period. The effects of the implantation on tissue water content are discussed in relation to NMR T1 relaxation times, and the relevance to whole-body NMR imaging of elevated T1 values due to nonmalignant pathological states is considered.

Animals↗
PubMed1979

Cranial scintigraphy: value of adding emission computed tomographic sections to conventional pertechnetate images (512 cases).

A prospective trial was carried out to assess the contribution made by a radionuclide transverse-section view to conventional radionuclide scans of the brain. Each set of scans was reported by two independent teams of observers, but only one team viewed the tomography section. An abnormality rating was used to decide whether a set of scans was positive or normal. The reports for 512 patients were analyzed and compared with the final independent diagnosis. Greater accuracy of diagnosis with the section view was significant at the 0.1% level; the results showed that failure to detect tumors was almost halved while there was a 16% improvement for the detection of infarcts. Abnormality ratings were also used to plot ROC curves and rating curves; these showed that the addition of the tomographic view increased markedly the proportion of true positives without any increase in the proportion of false-positive reports.

Brain Neoplasms↗
PubMed1978

Evaluation of x-ray CT (EMI scan) and isotope brain studies, including radioisotope axial tomography.

A comparison is made of the results of computer-assisted X-ray tomography (EMI scan) and those of radionuclide brain scan supplemented by computer-assisted isotope tomography. The X-ray examination shows a wider range of positive diagnosis, but the radionuclide examination is complementary in the detection of supratentorial gliomas. A similar comparative value of the isotope tomogram is noted in the detection of cerebral infarcts.

Brain↗
PubMed1977

Value of radioisotope axial tomography in the diagnosis of a cystic malignant glioma.

A case is presented in which the patient had a deep tumour in the posterior aspect of the temporal lobe close to midline. The brain scan including a transverse section view at 8 cm from the vertex was negative and the other neuroradiological examinations inconclusive. One month later a follow up brain scan was performed and the conventional views were negative whereas the transverse section scan done at 10 cm from the vertex showed a lesion in the left temporo-parietal region and near midline. Three months later a repeat brain scan was done, and the lesion was visualized in the conventional views and confirmed by angiogram.

Adult↗
PubMed1977

Electron spin resonance as a useful technique in the management of Hodgkin's disease.

Electron spin resonance spectroscopy has proved a useful and simple technique for the measurement of levels of caeruloplasmin and iron transferrin in whole blood from 50 patients with Hodgkin's disease. Those patients with clinically active disease show higher caeruloplasmin levels and lower iron transferrin levels than those with inactive disease. The results indicate that these tests are good indicators of the state of the disease and that serial measurement of these parameters may help in early prediction of clinical reactivity and in monitoring response to treatment. The combined information from iron transferrin and caeruloplasmin levels appears to be more predictive than that from the erythrocyte sedimentation rate and neutrophil alkaline phosphatase score.

Adolescent↗
PubMed1977

Lyoluminescence dosimetry with some saccharides.

Lyoluminescent properties of mannose, glucose monohydrate, sucrose and trehalose dihydrate were investigated from the point of view of suitability as dosimetric materials in a new system of solid state dosimetry. Distilled water was used as a solvent. With a reader equipped with an uncooled PM tube it was possible to measure doses of X- and gamma-rays in the range from a few rad to about 100 krad. Various experimental factors which could affect the dose measurements using lyoluminescence are discussed, including the energy response for X-rays. Some preliminary information on the response of saccharides to fast neutrons is also included.

Disaccharides↗
PubMed1977

Diagnostic value of computerised isotopic section renal scanning.

Isotope section renal scanning in the diagnosis of kidney disease has been compared with ultrasonic examination adn specialised radiological techniques. The computerised isotope tomographic section technique developed in Aberdeen has increased the accuracy and differential diagnosis of renal lesions especially cysts and tumours.

Humans↗
PubMed1973

A study of electron spin resonance spectra of whole blood from normal and tumour bearing patients.

Electron spin resonance spectra have been obtained from samples of frozen whole blood or separated blood cells and plasma. Blood samples were obtained from human controls having no diagnosed malignancy and from patients with a variety of benign and malignant tumours.The characteristic spectrum from control blood shows two main lines with g values of 4·2 and 2·049. Several smaller lines can also be observed. The line at g = 2·049 may be due to the copper protein ceruloplasmin. Although no qualitative differences could be found between the spectra from controls and cancer patients, samples from patients with certain types of tumour showed a significant increase in size of the g = 2·049 signal above control values. This was most noticeably the case with Hodgkin's disease and to a lesser extent with cancers of the breast. Squamous cell carcinomata, taken as a group, did not show an elevation in average size of the g = 2·049 signal. In this latter group, however, there were some indications that the effects of chemotherapeutic treatment could be followed during the early stages of such treatment. Examples are given in which onset of treatment with various cytotoxic agents was associated with reduction in size of the g = 2·049 signal.

Blood Cells↗