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Biomedical subjects

A V Persson

Publications and source records attributed to A V Persson.

At least 37 records · Page 2Linked to original sources
PubMed1985

Use of directional Doppler flow meter in noninvasive evaluation of aortoiliac segment.

Noninvasive peripheral arterial studies that include analysis of the Doppler velocity waveform from the common femoral artery can be helpful to the clinician in treatment of patients with peripheral arterial occlusive disease of the lower extremities. A normal waveform, one that demonstrates a reverse flow component in early diastole, is a highly accurate indication of a normal lumen of the aortoiliac artery. An abnormal waveform, one that lacks reverse flow, indicates a severe stenosis or occlusion in the more proximal arterial segment, a totally occluded superficial femoral artery with a severe stenosis of the deep femoral artery, or a technical error. When the clinical findings are correlated with noninvasive laboratory data, it is possible to distinguish which of these three abnormal situations exist in a given patient.

Adult↗
PubMed1985

The natural history of total occlusion of the internal carotid artery.

We believe that total occlusion of the internal carotid artery is not a hallmark of end-stage atherosclerosis. We were unable to identify any factor that would place patients at particular high risk for the development of further problems. The status of the opposite carotid artery or a history of previous operation did not predict which patients would experience further neurologic episodes. New disease seems to be the most important factor influencing the incidence of new neurologic events. We therefore recommend that these patients be followed closely with serial noninvasive testing to identify such new disease. On the basis of these data we have adopted the policy that patients in whom new symptoms or severe new disease or both develop are considered candidates for operation.

Arterial Occlusive Diseases↗
PubMed1985

Subacute massive thromboembolic occlusion of a main pulmonary artery. Report of a case successfully treated by thrombolytic therapy and review of the literature.

Subacute massive thromboembolic occlusion of the left main pulmonary artery in a 52-year-old woman is described. This disease remains a rare entity with a much less dramatic presentation than acute massive pulmonary embolus. The presenting symptom was unexplained dyspnea. Physical signs and laboratory tests were nonspecific. The perfusion scan is the best screening test for this disorder. Antemortem diagnosis is established by pulmonary angiography. A literature review undertaken to ascertain the incidence of this entity as well as to recommend treatment of choice, be it medical or surgical therapy, was unrewarding. We decided to use thrombolytic therapy and found a marked improvement in the patient's symptoms and perfusion scan after 24 hours. Although thrombolytic therapy is commonly indicated for acute massive pulmonary embolism, we believe this mode of therapy should also be the initial treatment for subacute massive pulmonary thromboembolism.

Anticoagulants↗
PubMed1984

Burst therapy. A method of administering fibrinolytic agents.

The use of noninvasive studies to establish the diagnosis and to follow the clinical course of patients undergoing fibrinolytic therapy markedly reduces the amount of invasive alternatives and their attendant bleeding complications. Streptokinase administered by the burst therapy protocol is very effective. Streptokinase administered in this fashion is very cost effective and is in keeping with the current economic trends. Administering warfarin the evening before the last burst of streptokinase markedly reduces the time required to adequately anticoagulate the patient with warfarin. Administering acetaminophen before and during therapy decreases the incidence of febrile reactions. Although streptokinase therapy is not without significant complications, the benefits outweigh the attendant risks.

Arterial Occlusive Diseases↗
PubMed1983

The natural history of carotid plaque development.

Fifty-seven carotid artery plaques in 54 patients were harvested at surgery and studied. Preoperative noninvasive findings, arteriograms, clinical symptoms, surgical findings, and light microscopic findings were compared. Thirty-four patients had symptoms, 28 with TIAs and six with a previous stroke. Thirty-three of the 34 had intraplaque hemorrhage, and 28 had a connection between the hemorrhage and the arterial lumen. Eleven of the 21 asymptomatic patients also had an intraplaque hemorrhage, and one had a connection. In eight of the 11, noninvasive studies showed progression of disease. The development of an intraplaque hemorrhage appears to be an important factor in an innocent plaque's becoming a clinically relevant one. If a connection develops between the intraplaque hemorrhage and the arterial lumen, the patient may have TIAs.

Aged↗
PubMed1983

Carotid body tumor. The Lahey Clinic experience.

We believe that paragangliomas of the carotid body should be excised in all patients unless formidable medical conditions prohibit the use of general anesthesia. If these tumors are left unresected, they will eventually grow to invade the skull and kill the patient. With definitive diagnostic modalities available, in addition to comparatively low-risk anesthesia, autotransfusion, and replacement of the carotid artery, there are few patients who cannot be surgically treated. The important point is that although such a tumor is rare, its presence must always be considered when dealing with a lateral neck mass. Carotid arteriography should be performed when a carotid body tumor is suspected.

Carotid Arteries↗
PubMed1982

Unilateral white matter necrosis following carotid endarterectomy.

The authors report the first known example of hypoxic-ischemic white matter necrosis limited to one cerebral hemisphere. The patient was a 63-year-old man who developed signs of a stroke following a myocardial infarct after a left carotid endarterectomy and died seven days later. At autopsy, extensive necrosis of centrum semiovale was found only in the cerebral hemisphere supplied by the endoarterectomized carotid artery. A recent thrombus was found at the site of the endarterectomy, and the right common carotid artery was completely occluded by an old thrombus. This observation probably is explained by a well-established collateral blood supply to the right cerebral hemisphere, which protected it from the effects of the hypotension that accompanied the myocardial infarct.

Autopsy↗
PubMed1982

Noninvasive testing for carotid artery stenosis: II. Clinical application of accuracy assessments.

Determination of the specificity, sensitivity, and accuracy of diagnostic tests usually identifies the value of the tests in isolation, but the clinical significance of the findings is less clear. In this study the accuracies of direct continuous wave color-coded Doppler imaging (DDI), periorbital directional Doppler ultrasonography (PDDU), and oculoplethysmography-carotid phonangiography (OPG-CPA) were calculated for each examination alone and in combination with others for 176 patients who had been studied by all three noninvasive methods for suspected extracranial carotid arterial disease. When evaluated alone, DDI yielded the highest accuracy, 94%. In 89% of the population, DDI agreed with at least one of the other two tests. When this occurred, the majority finding was correct 98%. When DDI disagreed with the other two tests (11% of cases), it was correct in only 50%. These findings suggest a clinical approach which would minimize testing while achieving a high accuracy for most patients and identifying those patients whose carotid status could not be discerned with these studies.

Carotid Artery Diseases↗
PubMed1982

Monoclonal antibodies to rabbit liver cytochrome P-450LM2 and cytochrome P-450LM4.

Monoclonal antibodies were prepared from hybridoma clones isolated by the fusion of myeloma cells and spleen cells derived from mice immunized with either purified rabbit liver microsomal cytochrome P-450LM2 or cytochrome P-450LM4. Seven hybridoma clones produced three kinds of monoclonal antibodies to P-450LM2. The first class bound, precipitated, and inhibited the enzyme activity of P-450LM2 for both benzo[a]pyrene hydroxylation and 7-ethoxycoumarin deethylation. The other two classes either bound and precipitated or only bound the enzyme. These monoclonal antibodies to P-450LM2 showed a precipitin reaction and inhibition of enzyme activity that was specific for cytochrome P-450LM2. Thus, they did not react with or inhibit the enzyme activity of the other isozyme cytochrome P-450LM4, Fraction 1 or Fraction 7. All of the monoclonal antibodies formed against P-450LM2 were mouse immunoglobulin (Ig) subclass IgG1. The most effective monoclonal antibody strongly inhibited the formation of oxygenated metabolites of benzo[a]pyrene at various positions as well as the deethylation of 7-ethoxycoumarin. Four hybridomas were isolated which produced monoclonal antibodies to P-450LM4. One of the four was of the IgM class and three were of the IgG1 type. The four monoclonal antibodies bound to P-450LM4 but did not precipitate the enzyme, and did not bind to P-450LM2. The monoclonal antibody P-450LM4 complexes interacted with protein A, and the enzyme activity for benzo[a]pyrene hydroxylation could be removed by centrifugation. The high specificity and monoclonality of these antibodies suggest their potential usefulness for studying the genetics, regulation, and roles of the different isozymes of P-450LM in drug and carcinogen metabolism.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1981

Noninvasive testing for carotid artery stenosis: I. Prospective analysis of three methods.

Oculoplethysmography-carotid phonoangiography and periorbital directional Doppler sonography are two techniques widely used in the noninvasive evaluation of possible carotid artery disease. Recent advances with sonographic Doppler devices now permit measurement of blood velocities in the extracranial carotid arteries by direct scanning with a color coded Doppler imaging system. A prospective study involving 216 patients being evaluated for possible carotid insufficiency was carried out to compare the results obtained with these three methods. With stenosis 65% or greater at angiography, the accuracy of the Doppler imaging system was 94%, that of oculoplethysmography-carotid phonoangiography was 84%, and that of periorbital directional Doppler sonography was 80%. These results demonstrate that direct Doppler examination of the carotid bifurcation is superior to either of the other two techniques for the detection of carotid artery stenosis.

Angiography↗
PubMed1981

[Non-invasive explorations of the carotid arteries (author's transl)].

For the non-invasive evaluation of patients suspected of having extracranial carotid artery disease, the non-invasive vascular laboratory at the Lahey Clinic, Boston, Massachusetts uses three tests. Carotid phonoangiography (C.P.A.) by itself is 60% accurate, the Kartchner-McRae Oculoplethysmograph (O.P.G.) by itself 80% accurate, and the Echoflow doppler arterial imager, by itself 90% accurate. These examinations are used for surveillance of high-risk patients and to determine the need for carotid arteriography. In a series of 94 patients, the combination of these non-invasive methods yielded one false negative and 2 false positive studies, for an overall accuracy of 95%.

Auscultation↗
PubMed1980

On the possible relationship of cytochrome P-450 to alcohol metabolism: fundamental aspects of the microsomal hydroxylation system, including properties and interactions of the components.

Recent studies on the cytochrome P-450-containing enzyme system of liver microsomes have shown that the cytochrome is present as a number of distinct isozymes, one of which is induced in vivo by the administration of aromatic hydrocarbons, as well as several forms which are less well characterized and not known to be inducible. The various cytochromes exhibit partially selective but overlapping activities with a variety of substrates. Additional components are NADPH-cytochrome P-450 reductase, which binds to the cytochrome to form a tight 1:1 complex, phosphatidylcholine, and cytochrome b5, the role of which is still not clear. Recent evidence indicates that some of the components are mutually beneficial in favoring formation of a functional complex. For example, phosphatidylcholine enhances the binding of substrate and reductase to P-450LM2, reductase enhances the binding of phosphatidylcholine, and substrate (benzphetamine) facilitates the binding of reductase. The possible effect of ethanol on these interactions should be considered in evaluating the reported inhibition by high concentrations of ethanol of reactions catalyzed by liver microsomal cytochrome P-450.

Animals↗
PubMed1980

Carotid endarterectomy.

Thousands of carotid endarterectomies are now performed each year. In properly selected patients in the hands of competent surgeons, the mortality and morbidity rate should not exceed 2 per cent. Although the long-term results are good, this procedure is prophylactic, and a patient who has already sustained a fixed neurologic deficit will rarely be improved by increasing the blood flow in the carotid arteries. This procedure, probably more than any other in the armamentarium of the vascular surgeon, depends on meticulous attention to detail and careful and gentle handling of tissue.

Anesthesia, Endotracheal↗
PubMed1980

Clinical use of noninvasive evaluation of the carotid artery.

The noninvasive evaluation of carotid artery disease should include a battery of tests that includes one direct and one indirect assessment of the extracranial carotid arteries. The resulting data should be correlated with the clinical findings and the patient's general status so the risks and benefits of carotid endarterectomy may be determined. These studies are usually outpatient procedures and allow one to determine in the office which patients would benefit from carotid surgery and who should be followed serially. Carotid arteriography is reserved for those patients who will be subjected to surgery. In our hands, the combination of CPA, Kartchner-McRae OPG, and Echoflow fulfill these requirements. In a small number of patients the history, physical examination, and noninvasive studies are inconclusive. For most patients, we are able to make decisions as to the best therapy in the office and can discuss risks and benefits with patients and their families with an accuracy of approximately 95 per cent before hospitalization and arteriography are considered.

Auscultation↗