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Biomedical subjects

M J Chamberlain

Publications and source records attributed to M J Chamberlain.

At least 55 records · Page 3Linked to original sources
PubMed1978

Radionuclide angiocardiography, a noninvasive method for evaluating left ventricular ejection fraction and regional wall motion; comparison with contrast left ventricular angiography.

The efficacy of gated synchronous acquisition (GSA) after cardiac blood pool labelling in assessing left ventricular function (ejection fraction and regional wall motion) was evaluated in 31 patients within 24 hours of contrast left ventricular angiography. With the R-wave of the electrocardiogram as a physiologic marker, radionuclide data recorded into an on-line computer allowed construction of cardiac blood pool images during sequential periods of the cardiac cycle. The images, of high count density, have good spatial resolution and can be viewed repetitively in real time in a cine mode. The ejection fractions calculated from the left ventricular time-activity curves corrected for background activity correlated well with the ejection fractions determined from dimension analysis of the contrast left ventricular angiograms (r = 0.87). The results were highly reproducible (r = 0.97). Results of analysis of left ventricular wall motion were similar with the two types of angiograms in 26 of the 31 subjects. GSA is a simple, safe means of evaluating left ventricular ejection fraction and regional wall motion noninvasively.

Angiocardiography↗
PubMed1978

Diagnostic efficacy of tests for the detection of iron overload in chronic liver disease.

The value of tests for the detection of body iron overload was investigated in 8 patients with clinically manifest primary hemochromatosis, 12 patients with cirrhosis and iron overload and 20 patients with liver disease and low or normal iron stores. Iron overload was defined as the presence of stainable iron in more than 50% of hepatocytes in a liver biopsy specimen. The percentages of patients with a true-positive (abnormal) or true-negative (normal) result were: serum iron concentration 65%, transferin saturation 85%, serum ferritin concentration 78%, serum ferritin:serum glutamic oxaloacetic transaminase (SGOT) index 78%, percent iron absorption 58%, percent iron absorption in relation to serum ferritin concentration 80% and percent iron absorption in relation to serum ferritin:SGOT index 93%. The calculated predictive value of a normal test result for the exclusion of iron overload in patients with liver disease, a group with an assumed prevalence of iron overload of 10%, was 98% to 99% for transferrin saturation and serum ferritin concentration used alone and 100% for these measures used together; the predictive value of an abnormal result for the diagnosis of iron overload was less than 50% for all of the above measures used alone or in combination. Hence, in patients with an increased serum ferritin concentration or transferrin saturation, or both, determination of the hepatocellular iron content of a specimen from a percutaneous liver biopsy is required for the diagnosis of iron overload.

Adolescent↗
PubMed1978

Stress myocardial imaging in mitral leaflet prolapse syndrome.

Mitral leaflet prolapse syndrome has been associated with anginal chest pain, atypical chest pain, electrocardiographic abnormalities and positive stress electrocardiograms. These features overlap those of ischemic heart disease. Furthermore, coronary artery disease is frequently associated with mitral leaflet prolapse. This study evaluated the usefulness of stress myocardial scintigraphy in distinguishing these two disorders. Thirty-two patients with an angiographic diagnosis of mitral leaflet prolapse were studied. Of the 22 patients (8 men and 14 women, mean age 48 years) with a normal coronary arteriogram, 5 had "typical" angina pectoris, 6 had resting electrocardiographic abnormalities and 6 had a positive stress electrocardiogram; all 22 patients had a normal stress myocardial scintigram. Of the 10 patients (7 men and 3 women, mean age 55 years) with at least 70 percent stenosis of one coronary artery, 6 had "typical" angina pectoris, 1 had resting electrocardiographic abnormalities and 7 had a positive stress electrocardiogram. Nine of these 10 patients had one or more demonstrable perfusion defects on stress myocardial scintigrams. It is concluded that mitral leaflet prolapse syndrome is not associated with regional myocardial ischemia as demonstrated with stress scintigraphy, and that stress scintigraphy, a noninvasive technique, is useful in distinguishing the mitral prolapse syndrome from mitral prolapse associated with coronary artery disease.

Adult↗
PubMed1978

Measurement of dietary cadmium absorption in humans.

Total body counting was used to determine cadmium absorption in 14 healthy subjects and in 1 patient with an ileostomy. Breakfast was extrinsically tagged with 115mCdCl2, and a poorly absorbed marker, 51CrCl3, was added to determine the point of complete elimination of unabsorbed radiocadmium from the gastrointestinal tract. The 51Cr was not an ideal marker: fecal excretion of radiocadmium continued beyond the point at which chromium was completely eliminated from the body, Nevertheless, it was helpful in six subjects in identifying the presence of unabsorbed radiocadmium still in transit in the lumen of the gastrointestinal tract 3--5 wk after the test meal. The average body retention of radiocadmium determined between 7 and 14 d after the disappearance of the chromium marker from the body was 4.6 +/- 4.0% (SD), with a range of 0.7--15.6%. The biological half-time of absorbed radiocadmium in one of the subjects was 100 d.

Adult↗
PubMed1978

Noninvasive assessment of patients following aortocoronary bypass surgery.

A simple, accurate, noninvasive method is required for the objective evaluation of aortocoronary bypass surgery. Stress myocardial imaging with intravenous injection of potassium-43 or thallium-201 was used an average of 4.4 months after direct myocardial revascularization in 77 patients to assess the accuracy of stress myocardial imaging in predicting completeness of revascularization. The results were correlated with maximal treadmill exercise tests, extent of revascularization and status of bypass grafts (occlusion, stenosis and distal disease). We found stress myocardial imaging to be a more sensitive method than the stress electrocardiogram for the detection of incomplete revascularization. The method appears to be a sensitive noninvasive means of evaluating the results of aortocoronary bypass surgery.

Coronary Angiography↗
PubMed1978

Increased dietary cadmium absorption in mice and human subjects with iron deficiency.

In mice fed a low iron diet, the addition of low levels of cadmium chloride (10 micrometer) to the drinking water impaired growth and accentuated the development of anemia. Cadmium had no effect on mice given a similar diet supplemented with iron. Iron deficiency increased the concentration of cadmium in the duodenal mucosa, the transfer of cadmium to the body from the intestinal tract, and the deposition of absorbed cadmium in the kidneys. In human subjects, the average absorption of 25 microgram of cadmium, labeled with 115mCd, from a test meal was 8.9 +/- 2.0% (mean +/- SE) in 10 people with low body iron stores (serum ferritin less than 20 ng per ml) and 2.3 +/- 0.3% in 12 subjects with normal iron stores (serum ferritin greater than 23 ng per ml). The biological half-time of the radiocadmium in 3 of the subjects ranged from 90 to 202 days. Thus, the intestinal adaptive response to iron deficiency in both experimental animals and human subjects leads to the increased absorption of cadmium, a potentially toxic element.

Anemia, Hypochromic↗
PubMed1977

Predictive value of myocardial perfusion imaging for aortocoronary bypass surgery.

Evaluation of patients for aotocoronary bypass (ACB) surgery is dependent on the findings at cardiac catheterization. Left ventricular angiography cannot distinguish between reversible and irreversible myocardial dysfunction. In 82 patients macroaggregates of human serum albumin, labelled with iodine-131, were injected before operation into the right coronary artery and technetium-99m labelled microspheres were injected into the left coronary artery. Two weeks after operation similar technetium-99m and iodine-131 injections were made into the native vessels and grafted vessels, respectively. Myocardial distribution of the 20 mu particles was visualized with a rectillinear scanner. Sixty-seven patients had normal myocardial perfusion scans preoperatively even though wall motion was abnormal in 34. There was substantial improvement in the left ventricular function of these 34 patients; the mean ejection fraction increased from 56 to 65%. Fifteen patients had abnormal myocardial perfusion scans; improvement in left ventricular function in this group occurred only if the bypass graft was made to an area with normal regional perfusion preoperatively. It is certain that an adequate capillary bed is present if the myocardial scan is normal, regardless of the degree of critical stenosis in either coronary artery. The patient with a completely occluded coronary artery and normal myocardial scan is a good candidate for ACB and will show improved left ventricular contraction if the ACB is patent,

Angina Pectoris↗
PubMed1976

Malfunction of tricuspid valve prosthesis shown by isotope angiocardiography.

Isotope angiocardiography established prosthetic tricuspid valve obstruction in a patient 6 years after triple valve replacement. Thrombus formation is a common complication of prosthetic cardiac valves, particularly in the tricuspid position where engagement of cage with myocardium is an additional potentially obstructive hazard. Comparison is made between the information yield of the isotope investigation and cardiac catheterization with contrast cineangiography. It is suggested that the isotope technique can noninvasively provide valuable anatomic and functional data, particularly where the right side of the heart is to be examined.

Adult↗
PubMed1975

Osteomalacia and carcinoma of prostate with major redistribution of skeletal calcium.

A case of hypophosphataemic osteomalacia occurring in association with a carcinoma of prostate is described. Although only palliative treatment to the primary tumour was possible, worthwhile remission of bone symptoms, due to osteomalacia, was achieved with pharmacological doses of vitamin D. The presence of extensive skeletal metastases modified the radiological features of osteomalacia. Major alterations in the distribution of calcium within the skeleton were observed during a period when total body calcium remained unaltered. This observation may be of relevance to other cases in which osteosclerotic metastases develop.

Acid Phosphatase↗
PubMed1973

Osteoporosis and long-term corticosteroid therapy.

Sequential measurements of total body calcium by in-vivo neutron activation analysis were made in five patients treated with corticosteroid drugs for severe inflammatory disease. No evidence of osteoporosis was seen to develop during the course of 20-33 months of study. In one case a substantial rise in total body calcium was found.

Activation Analysis↗