PubMed Health⌕ Search

Biomedical subjects

K McKusick

Publications and source records attributed to K McKusick.

14 recordsLinked to original sources
PubMed1989

Correlation of postoperative bone scintigraphy with healing of vascularized fibula transfer: a clinical study.

This study examines the usefulness and reliability of bone scintigraphy in correlation with radiological and clinical evidence of bone healing in 15 patients who underwent microvascular transfer of the fibula. All patients were followed for a minimum of 18 months postoperatively. Technetium-99 methylene diphosphonate bone scans and the most recent radiographs were blindly rereviewed. Bone scintigraphic results were characterized as (1) clearly positive (i.e., excellent visualization of the fibula), (2) clearly negative (i.e., no evidence of tracer uptake in the fibula), or (3) indeterminate (i.e., artifact present as a result of metallic or soft tissue interference). Bone radiographs were classified into three typical patterns: (1) complete bony union and graft hypertrophy, (2) incomplete union (either distal or proximal) requiring a second procedure), and (3) nonunion, with increased proximal and distal lucency (with or without pathological fracture) and loss of graft definition. Eleven patients had positive scintigraphic scans postoperatively. In 8 no subsequent procedure was necessary; 2 patients required additional bone grafts to augment the osseous reconstruction; viable fibulas were seen at reoperation. One patient with a positive scan showed decreased graft definition at four months followed by autograft fracture. Three patients had indeterminate scans, 2 of whom evidenced uncomplicated clinical and radiological union. One patient had a clearly negative scan and ultimately tibia-fibula synostosis was required to attain stability. Bone scintigraphy appears to correlate with survival, but not necessarily union, of a vascularized fibula autograft. Additional monitoring techniques should be used in combination with a one-time bone scan to both monitor the patency of the microanastomoses and to prioritize the orthopedic management of the patient.

Arteries↗
PubMed1986

The utilization of Tc-99m-TBI as a myocardial perfusion agent in exercise studies: comparison with Tl-201 thallous chloride and examination of its biodistribution in humans.

Twenty-four patients were studied with both 201Tl-thallous chloride and 99mTc-TBI scintigraphy following exercise. Comparison of the two agents in detecting segmental myocardial ischemia and scar was made in 18 patients with evidence of coronary artery disease on 201Tl-thallous chloride scintigraphy. Agreement between the two studies was observed in 77% (125 of 162) of left ventricular segments, suggesting that 99mTc-TBI can be used as a myocardial perfusion agent. Limitations were related to early high background activity from lungs and liver. The high lung activity and early myocardial redistribution within the 1st hour contributed to the failure of 99mTc-TBI to detect 16 segmental defects seen in the immediate post-exercise thallous chloride scan. Persistently high liver activity additionally affected accurate interpretation in the left ventricular segments close to the diaphragm. Improvement in the accuracy of 99mTc-TBI stress studies might be achieved with tomographic imaging to reduce the problem of background activity or by the development of 99mTc-labeled isonitrile analogues with rapid lung and liver clearance.

Adult↗
PubMed1986

Ventricular volume and ejection fraction in the diagnosis of the aetiology of low cardiac output in burned patients.

Cardiovascular instability following burns may result from either cardiac or non-cardiac causes. We illustrate three cases in whom routine measurements of atrial filling pressures and cardiac output alone did not reflect the adequacy of blood volume or the myocardial performance. In each instance, measurements of ventricular volume and ejection fraction by thermodilution technique or 99mTC ventriculography were useful to determine the actual causes of decreased cardiac output.

Adult↗
PubMed1985

Comparison of three semiautomatic methods for determination of left ventricular ejection fraction from gated cardiac blood pool images.

A number of computer programs exist for the determination of ejection fraction from gated blood pool images. Three commercially available algorithms were compared on the same radionuclide data from 50 catheterized patients. The methods used were: (1) simple thresholding, (2) second derivative edge determination, and (3) a combination of these two. There was good correlation with catheterization ejection fraction for all three methods using smoothed data [r = 0.781, 0.77, 0.84 respectively (P less than 0.01)]. However, interobserver variance was significantly decreased (P less than 0.01) by use of the second derivative method when compared with the other two methods and catheterization. Thus, if accuracy and low interobserver variance are required, then a combination of a second derivative and thresholding method is preferable.

Cardiac Catheterization↗
PubMed1985

Cell specificity of rat cytokeratin p39 during azo dye-induced hepatocarcinogenesis.

Monoclonal or affinity-purified antibodies specific to Novikoff hepatoma cytokeratin p39 were employed to study the origin and fate of p39-containing cell types during hepatocarcinogenesis induced with N,N-dimethyl-p(m-tolylazo)aniline. Frozen sections were obtained from the livers of animals autopsied temporally during carcinogen feeding and were assayed immunohistochemically. In normal, untreated liver or in liver from animals fed the hepatotoxin alpha-naphthyl-isothiocyanate, the localization of p39 was restricted to bile duct epithelial cells while hepatocytes were non-reactive. However, during carcinogen treatment we observed a sequential appearance of immunoreactive cells which were similar morphologically to the classical 'oval' cells of hepatocarcinogenesis; eventually these cell types were enriched around the preneoplastic hepatocyte nodules. Occasional transformed hepatocytes within the nodules exhibited strong immunoreactivity. In the later stages of hepatocarcinogenesis, these antibodies stained the epithelial cells in areas of severe adenosis as well as the neoplastic epithelial cells of cholangiomas and some, but not all, hepatocellular carcinomas. Our results document the presence of p39 in the 'oval' cells of hepatocarcinogenesis and indicate that some populations of transformed hepatocytes exhibit this cytokeratin after transformation.

Animals↗
PubMed1984

Detection of pulmonary emboli after total hip replacement using serial C15O2 pulmonary scans.

15-O-labeled carbon dioxide (C15O2) was used for the detection of preoperative and postoperative pulmonary emboli in seventy-three patients, more than forty years old, who had undergone a total hip replacement. When the C15O2 scan was suggestive of pulmonary embolism, it was followed by conventional perfusion and ventilation (V/Q) scans. If these also suggested the presence of embolism, pulmonary angiography was done. Three different prophylactic agents against venous thromboembolic disease had been used in the seventy-three patients. Seventeen (23 per cent) of the seventy-three patients had a positive C15O2 pulmonary scan followed by a positive ventilation-perfusion scan and a positive pulmonary angiogram that showed pulmonary emboli. Fourteen (83 per cent) of these patients with proved pulmonary emboli were asymptomatic. Fifteen additional patients also had a positive C15O2 scan. However, twelve of them had either negative ventilation-perfusion scans or chest radiographs that demonstrated atelectasis, and did not have a pulmonary angiogram. Three patients with a positive C15O2 scan had a negative pulmonary angiogram. Two of them had a ventilation-perfusion scan that was interpreted as showing probable pulmonary emboli, and the remaining patient did not have a ventilation-perfusion scan. Forty-six per cent of the patients with positive C15O2 scans did not have pulmonary emboli. This sensitive and readily repeatable test provides an excellent means of detection of silent emboli, an improved method of evaluating the efficacy of prophylactic agents, and the opportunity to correlate the site, size, and onset of deep-vein thrombosis with pulmonary emboli in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Cardiovascular nuclear medicine current applications and the outlook for 1985.

There has been a rapid assimilation of nuclear imaging techniques into the armamentarium of physicians caring for cardiovascular disease patients. The most widely used tests have been thallium uptake and clearance for myocardial perfusion, and gated blood pool imaging for measurements of regional and global ventricular function. Understanding of the dynamics of the procedures has led to appreciation of the sensitivity of alterations in pulmonary distribution of those radiopharmaceuticals in predicting the presence of increased pulmonary capillary wedge pressure, the augmentation of thallium clearance by eating, and the complexity of the response of the ejection fraction to exercise. Applications of an ambulatory device for ventricular function testing, labeled myocardial metabolic markers, and vascular integrity agents such as labeled lipoprotein may characterize the directions taken in the last half of this decade.

Coronary Disease↗
PubMed1979

Early diagnosis of disk space infection with 67Ga in an experimental model.

Both 67Ga and 99mTc scans become positive in experimental disk space infection, but 67Ga does so earlier than 99mTc. The radiologic features of experimental disk infection are similar to those seen clinically. Disk infection commences primarily in the disk and not in the vertebral body. Gallium-67 is useful in diagnosis of the disease under circumstances when the diagnosis is in doubt.

Animals↗
PubMedDate not supplied

[Simultaneous test of ventricular function and myocardial perfusion, during exercise, using a new agent labeled with Tc99m].

One a tribute of a Tc 99m labeled myocardial agent is the possibility to measure both ventricular function and myocardial perfusion with a single injection. To assess this, normal volunteers, 14 patients with coronary artery disease (CAD) and two suffering from cardiomyopathy with normal coronaries, were injected with 8-10 mci carbomethoxy-isopropyl-isonitrile or 20 mci Rp-30 Tc 99m at peak semi-recumbent bicycle exercise and again at rest. Thirty msec per frame first pass data, and 5 min static anterior, 40(0-) and 70(0-) left anterior oblique images were obtained. Standard Thallium 201 stress test were also done, within one month, and were at the same level of exercise. The left ventricular ejection fraction (EF) increased with exercise (69%-76%) in normal patients. All studies showed normal myocardial perfusion on exercise. In CAD patients the EF increased in some patients who had ischemia. Perfusion images with Tc 99m during exercise and at rest had an identical correlation with Thallium 201. The results support the concept of dual ventricular function and perfusion studies using a single Tc 99m labelled myocardial agent, and suggest that this could become the standard radionuclide stress tests in the future.

Angina Pectoris↗
PubMedDate not supplied

Pain as an indicator of bone metastasis.

Patients with breast or prostate cancer routinely referred for bone scintigraphy were evaluated for the presence of skeletal pain, as determined by a self administered questionnaire. Pain was a common finding, whether or not metastatic disease was present, and occurred in over half of patients. Although most patients with bone metastases did report bone pain, a significant fraction (21% of breast and 22% of prostate patients) were asymptomatic. A distinct minority of individual anatomic regions of metastasis were painful: pain was reported in 23% of sites of breast metastases and 15% of metastatic prostate cancer sites. Of all sites at which pain was present, metastases were demonstrated in only about one half. These results indicate that pain is not a reliable indicator of the presence of location of metastatic bone disease.

Adolescent↗