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Biomedical subjects

M B Clarke

Publications and source records attributed to M B Clarke.

7 recordsLinked to original sources
PubMed1978

Hepatobiliary imaging: a comparison of 99Tcm-dihydrothioctic acid and 99Tcm-pyridoxylidene glutamate in the non-jaundiced patient.

A comparison of two hepatobiliary imaging agents, 99Tcm-dihydrothioctic acid (99Tcm-DHT) and (99Tcm-pyridoxylidene glutamate (99Tcm-PG) has been carried out in 44 non-jaundiced patients. Thirty-one patients were admitted for investigation of upper abdominal pain and 13 patients were volunteers who were undergoing treatment for unrelated conditions. Satisfactory liver images were obtained with both agents in patients without liver disease, but they were inferior to those seen after 99Tcm-sulphur colloid. 99Tcm-PG produced clearer images of the gall-bladder and bile ducts than 99Tcm-DHT. Non-visualization of the gall-bladder was interpreted as gall-bladder disease; in patients with inflammatory gall-bladder disease no gall-bladder image was seen (nine 99Tcm-DHT, nine 99Tcm-PG). The gall-bladder was also not demonstrated in two of the volunteers' group (one 99Tcm-DHT, one 99Tcm-PG), nor was a gall-bladder seen in five patients whose abdominal pain was not due to acute cholecystitis. Despite this, there was agreement between the results of imaging and oral cholecystography in 21 out of 22 subjects. 99Tcm-PG is non-toxic, cheap and rapidly excreted by the liver into the bile. A 99Tcm-PG scan would be useful when rapid diagnosis is required in suspected acute cholecystitis when conventional contrast radiology is unlikely to be of value.

Adult↗
PubMed1978

Hepatobiliary imaging: the use of 99Tcm-pyridoxylidene glutamate scanning in jaundiced adults and infants.

99Tcm-pyridoxylidene glutamate (99Tcm-PG) scans have been carried out in 24 jaundiced adults (mean total bilirubin 255 mumol/l and 11 infants with prolonged obstructive jaundice (mean total bilirubin 165 mumol/l). Absence of radioactivity in the gut was interpreted as complete biliary obstruction which was the cause of jaundice in ten adults and six infants. Using this criterion occlusion or patency of the bile ducts was correctly determined in 21 adults and eight infants. False-negative gut images were found in one adult and two infants, and three scans were inconclusive (two adults, one infant). The scan was unable to show details of the site of obstruction or pathology but the technique was simple and atraumatic and was safely performed in patients with serious complications, e.g. renal failure, coagulation defects, septicaemia. In infants the 99Tcm-PG scan compared well with the 131I rose bengal faecal excretion test and with liver biopsy in the investigation of prolonged obstructive jaundice. Repeat scans in infants with biliary atresia were used to assess postoperative bile drainage. It is suggested that 99Tcm-PG scanning is useful screening test in difficult cases of jaundice. It is especially useful in frail patients, and patients with complications.

Adult↗
PubMed1977

Physical characteristics and ventilatory function of 404 commercial divers working in the North Sea.

The physical characteristics and simple lung ventilatory indices (FVC, FEV 1, FEV 1/FVC) of 404 commercial divers employed by companies operating in the North Sea were analysed. These findings were correlated with the diving experience and maximum operating depth of each diver. All the divers were men of average height 176-9 cm, and weight 77-1 kg which is greater than average for active Western males, but only 6% were more than 120% of their predicted weight. The average duration of commercial diving was 7-1 years, 11% of divers having less than one year's experience. Sixty-seven per cent had worked at a maximum depth of 200 ft (61 m) and only 6% had worked deeper than 500 ft (153 m). The mean forced vital capacity (FVC) was 120-4% of the predicted value which indicated that they could voluntarily move large amounts of gas in and out of their lungs. This was greatest in the divers who when deepest. The mean forced expired volume in one second (FEV 1) was 117% of the predicted value showing that expiratory airflow capacity was also increased, but to a lesser extent than the FVC. Thper and activated by zinc. Plasma protein protected the enzyme from both inhibition and activation. ALAD activity was found to be an indicator of the total metal ion concentration in the blood and was therfore considered to be of doubtful value in screening large population for increased lead absorption.

Adolescent↗
PubMed1976

Factors involved in the detection of pulmonary emboli by labelling techniques.

Experiments were set up to assess quantitatively the problem of detecting, by scanning and gamma-camera, labelled pulmonary emboli in the presence of background radioactivity. In vitro, a relative concentration of radioactivity of 2:1 was required to detect a 1-1 cm diameter "hot spot". The results in vivo suggest that the level of radioactivity of a pulmonary embolus situated in the centre of the lung field should be at least six times that of the circulating blood.

Animals↗
PubMed1976

Liver and gall-bladder imaging with technetium-99m dihydorthioctic acid and technetium-99m pyridoxylidene glutamate-a study in the young pig.

Seventeen scans on ten young pigs were performed after injection of Technetium-99m labelled dihydrothioctic acid (99Tcm-DHT) and Technetium-99m labelled pyridoxylidene glutamate (99Tcm-PG) using a gamma-camera. Sequential images of the liver, gall-bladder and intestine were observed in all healthy animals. 99Tcm-DHT produced the clearer liver images, whereas 99Tcm-PG produced more rapid and intense gall-bladder images. Analysis of hepatic bile in three animals also suggested a more rapid and higher concentration of 99Tcm-PG than 99Tcm-DHT (36% vs. 4% of the injected dose over two hours). Bowel images were not seen in an animal that had undergone exicision of the extrahepatic biliary tract, but scans performed after hepaticojejunostomy demonstrated intestinal transit of isotope. This study shows that the hepatobiliary system can be easily imaged using Technetium-99m labelled compounds which are excreted into bile. These agents may be useful in the diagnosis of obstructive lesions of the extrahepatic biliary tract of adults and infants.

Animals↗