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Biomedical subjects

V Lopez-Majano

Publications and source records attributed to V Lopez-Majano.

17 recordsLinked to original sources
PubMed1991

Bone scan as a stratification variable in advanced prostate cancer.

The serial technetium 99 (99Tc) bone scans of 76 patients with Stage D-2 prostate cancers were reviewed. Sites of metastases in skeletal areas in decreasing order were vertebrae, ribs, pelvis, long bones, and skull. Patients with one or two involved skeletal areas had a significantly longer progression-free interval and survival time than patients with three or more bony areas of uptake. Bone scans might be used as a stratification variable in future prospective clinical trials of Stage D-2 prostate cancer.

Aged↗
PubMed1990

Pulmonary blood flow distribution in erect man in air and during breathhold diving.

We used intravenously administered 99mTc-labelled macroaggregates and a gamma camera attached to a computer for measuring distribution of pulmonary blood flow per unit lung volume in eight healthy subjects sitting erect in air and also during breathhold diving to 1 or 10 m of depth. We measured distribution of perfusion in the supine position and substituted regional lung volume with regional perfusion in the supine for calculating regional perfusion per lung volume erect in air and during diving. The perfusion per unit lung increased rectilinearly down the lung in subjects below 30 years of age but decreased in the lowermost regions in older subjects. This decrease showed a strong correlation to closing capacity. An age-related decrease in transpulmonary pressure may influence both basal perfusion and closing capacity. During submersion, perfusion became equal in all regions with the exception of the lung apex which became hyperperfused. Close to the diaphragm, small inconsistent changes were noted. Redistribution was the same at surface (1 m of depth) with the lung volume being close to total lung capacity and at 10 m of depth when lung volume was compressed to functional residual capacity. During breathhold diving, high intrapulmonary blood volume and pressure became more important for blood flow distribution than gravity or lung volume, while differences in regional hypoxic vasoconstriction and in transpulmonary pressure seem to explain interindividual variation.

Adult↗
PubMed1979

Neoplasm localization with radionuclides.

Tumor scintigraphic localization of neoplasms can be done in two ways: indirectly and directly. The first method shows alternations of the normal structure of the organ, such as "cold lesions" in liver and thyroid. Abnormalities in function as increased permeability of the blood barrier results from abnormal deposition of the radionuclide in the brain scintigram of a patient with neoplasm. Increased focal areas of uptake of bone-seeking radionuclides are very characteristic of metastases. The direct methods depend on preferential uptake of the radionuclide by the neoplastic tissue resulting from altered metabolism (e.g. Se-75). Other agents such as Gallium-67 have affinity for neoplasms. Another approach is to use antineoplastic agents and radioactive antibodies which will localize in the tumor. At this stage the most useful neoplasm seeking agents are Gallium-67 citrate and 111In-Bleomycin, even though infections can give false positives. The possibility should be considered of enhancing the uptake of radionuclides by neoplastic cells using increased O2 concentration.

Animals↗
PubMed1979

Size of arteriovenous anastomoses in the dog femoral circulation.

Radioactive plastic microspheres 50 and 200 micra in diameter labeled with Ytterbium169 were used to study distribution in the femoral circulation of living dogs under general anaesthesia. Shunting was demonstrated because radioactivity was detected in the lungs after intraarterial injection of 50 micra microspheres. When the size of the microspheres injected was 200 micra no radioactivity was detected over the lungs. This indicates that the arteriovenous anastomoses are smaller than 200 micra, they are probably located in the skin because there was less radioactivity in the skin after intrafemoral injection of the 50 micra microspheres than when the injected microspheres were 200 micra in diameter.

Animals↗
PubMed1978

Indications for pulmonary function testing.

Pulmonary function testing is needed to determine the pathophysiology present in the patient with cardiopulmonary disease. Blood gases and pH should be obtained during emergency situations and during cranial, thoracic, and extensive cervical or abdominal surgery. Lung function tests can be divided in global such as spirometry and diffusing capacity which study the ventilation and transfer of gases and regional determinations of ventilation and perfusion. Both types of tests complement each other and should be used together. The spirometry should consist at least of determination of the vital capacity and is determined in the first second to ascertain if there is obstructive lung disease. Some tests such as flow-volume curves, alveolar-arterial gradients and closing volume are very useful to detect early pulmonary disease before any symptoms or findings are present. This is probably one of the most important medical indications for pulmonary function testing. Before certain types of surgery pulmonary function testing is indicated; if the spirometry and diffusing capacity tests are normal, there is no pulmonary contraindication for the planned surgery. In chest surgery if there is significant compromise of the spirometry and diffusing capacity regional lung function tests are indicated to study the pathophysiology at regional level, thus trying to circumscribe the lung resection to the diseased areas.

Blood Gas Analysis↗
PubMed1978

Incidence of pulmonary embolism.

During the last 5 years in a community hospital of 219 beds, the most common cause of death (primary and secondary or contributory) was pulmonary embolus. In the US fatal pulmonary emboli occur in 5 patients for 1,000 inpatients, nonfatal pulmonary embolism in 20 patients per 1,000 inpatients, about 142,000 patients suffer fatal pulmonary emboli and 568,000 suffer nonfatal pulmonary emboli each year. In 422 autopsies 93 patients (21%) have pulmonary emboli undiagnosed during the patient's life time. In comparing with other statistical studies, about 21% represent the death rate of patients treated for pulmonary emboli if the diagnosis is previously made. On the basis of this observation the incidence of pulmonary emboli and thrombosis of the lower limbs appears to be about the same in community and the university hospitals, disregarding if the patients are having the highly skill care or are treated by the general practitioner without the sophistication of expensive technology.

Adult↗
PubMed1978

Incidence of pulmonary embolism in deep venous thrombosis.

Abnormal radionuclide phlebograms were found in 65 patients in whom simultaneous-perfusion lung scintigrams and phlebograms were performed. All these patients were on adequate treatment with heparin for deep venous thrombosis. In 28% of the cases, the diagnosis of pulmonary embolism was made because they had abnormal perfusion lung scans with normal chest radiograph and clinical symptoms of pulmonary embolism.

Adolescent↗
PubMed1976

Quantification of lung scintigrams.

A simple method of obtaining objective information consists in recording numerical information of the counts in each lung. Albumin macroaggregates labeled with 99Tc(m) and a gamma camera with a data processor were used.

Humans↗
PubMed1976

Early diagnosis of interstitial fibrosis.

2 cases of interstitial fibrosis of the Hamman-Rich type are presented. The patients were symptomatic, but had normal X-rays. They were suspected of having interstitial infiltration by pulmonary function tests. Diagnosis was confirmed by lung biopsy. Pulmonary function tests, especially the study of elastic properties of the lung, can be of primary help in the diagnosis of pulmonary interstitial infiltration and fibrosis when the patient's X-ray is normal.

Adult↗
PubMed1976

Thromboembolic disease.

In 52 patients with pulmonary embolism, the deep venous circulation of the lower extremities and the pulmonary arterial blood flow were studied with albumin macroaggregates labeled with technetium-99m. A gamma camera with a data processor was used for this study. At the beginning, the perfusion lung scintigrams were abnormal in all the patients, 42 of them also had abnormal phlebograms and in half of them the perfusion by lung scintigram became normal when the phlebograms were obtained. These findings establish the high incidence of deep thrombophebitis in the legs of the patients with pulmonary embolism and indicate that the leg is of the most important 'thrombi factory' and that the deep venous circulation of the extremities should be studied to determine the primary cause of the pulmonary embolism.

Humans↗
PubMed1976

Distribution of the femoral circulation in living dogs.

The femoral circulation of living dogs was studied with plastic carbonized microspheres 50 and 200 micra in diameter, labeled with Yterbium169. The femoral blood flow is distributed in the following way: 35% of the particles 50 micra in diameter went to muscle, 45% of the same particles went to skin and 20% to bone. When the particles were 200 micra in diameter 16% went to muscle, 65% to skin and 19% to bone.

Animals↗
PubMed1975

Indications for lung scintigraphy.

Perfusion and ventilation lung scintigraphy are indicated: (1) for evaluating regional perfusion and ventilation, (2) for establishing a ratio between ventilation and perfusion in different areas of the lung, (3) when chest surgery is planned (especially for mapping out the extent of resection), (4) when surgery of the upper abdomen is to be performed, and (5) when global function studies are compromised. Regional ventilation and perfusion studies are invaluable in the diagnosis of pulmonary thromboembolism in which a perfusion defect is accompanied by well-preserved ventilation in the underperfused area. Regional function tests are indicated for evaluating the distribution of ventilation and pulmonary circulation in practically any chronic pulmonary disease, especially when global function studies, such as spirometry, show significant decreases.

Lung Diseases↗
PubMedDate not supplied

Dynamic studies with radionuclides.

Scintigraphy, the visual display of radioactivity, shows the size, shape and structure of the organ being studied. This information should be complemented with dynamic studies which will indicate the distribution of the radioactivity in the organ in relation to time. Dynamic studies must be performed with external detectors and the gamma camera. Circulation (systemic, pulmonary or cerebrospinal fluid) can be studied depending on the method of administration and the radionuclide used. The indicators are the same as for arteriography. Regional distribution of ventilation can be studied using radioactive gases. Regional distribution of ventilation of the lungs and mucociliary clearance can also be studied using inhaled particles. Dynamic studies do not replace but only supplement scintigraphy. They should be quantitated to obtain objective information.

Blood Circulation↗