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Biomedical subjects

J Dion

Publications and source records attributed to J Dion.

26 records · Page 2Linked to original sources
PubMed1977

Antinuclear antibody: predictive of lymphocyte response in rheumatoid arthritis.

The phytohemagglutinin induced response of lymphocytes was studied in two groups of rheumatoid patients differing only in the presence or absence of antinuclear antibodies (ANA). The response was found to be depressed in 16 ANA positive and normal in 14 ANA negative patients. Antinuclear antibody screening may serve as a simple method to identify a subgroup of immunodepressed rheumatoid patients who may be potential candidates for immunostimulation therapy.

Antibodies, Antinuclear↗
PubMed1975

Experimental immune arthritis: host factors.

An experimental chronic mono-arthritis was induced in rabbits using adjuvants and bovine serum albumin. The results suggest that unidentified host factors (possibly genetic) influence the induction of delayed hypersensitivity to the antigen. The data further show a clear correlation between systemic cell mediated immunity and chronic synovitis. When this condition is absent, there is a poor correlation between the humoral response and the arthritis. The results make difficult the interpretation of local immune complex deposition as the sole, chronic phlogistic stimulus. (J Rheumatol 2: 373-383, 1975).

Adjuvants, Immunologic↗
PubMedDate not supplied

MR imaging of acute subarachnoid hemorrhage.

The MR appearance of acute subarachnoid hemorrhage experimentally produced in Macaca monkeys and observed in patients with clinically documented acute subarachnoid hemorrhage is presented. Subarachnoid hemorrhages were produced in two Macaca Nemestrema monkeys using the technique of Frazee. CT and MR imaging were performed immediately after the procedure and at frequent intervals up to two week post hemorrhage. MR including T1 and T2 weighted multiplanar spin echo images were obtained. The imaging studies were compared with clinical evaluations and pathological specimens of all animals. Findings in the experimental animals are correlated with those observed in patients with clinically documented subarachnoid hemorrhage. The results show that acute subarachnoid hemorrhage (SAH) can be detected with MRI as isointense signal replacing normally black CSF spaces on T1 weighted images. Signal changes most likely relate to protein water binding associated with the clotting mechanism rather than oxidative denaturation of hemoglobin. Imaging performed experimentally and clinically beyond four days, however, showed a marked increase in signal intensity on T1 weighted images which probably does result from methemoglobin formation within the clot matrix. Although CT remains the gold standard in detecting acute SAH, MR does provide some sensitivity to its presence.

Acute Disease↗
PubMedDate not supplied

Preembolization functional evaluation in brain arteriovenous malformations: the superselective Amytal test.

PURPOSE: To describe our experience with the use of Amytal injected through a superselective catheter prior to planned embolization of cerebral arteriovenous malformations. MATERIALS AND METHODS: 109 superselective tests were performed with 30-mg injections of Amytal. All patients were evaluated by both clinical examination and EEG. RESULTS: Twenty-three of these tests were positive. There were no prolonged neurologic complications of the Amytal test. We also examined the value of EEG monitoring compared to clinical monitoring during the Amytal test. Of the 23 positive Amytal tests, only 12 showed a change on clinical exam (52%). This meant that almost half of the positive Amytal tests would have been falsely called negative (false negative rate of 10%). There were also three positive Amytal tests with changes on clinical examination without any change on EEG. CONCLUSION: The superselective Amytal test can be done safely as part of the interventional neuroradiologic procedure. Clinical and EEG monitoring of the patient are essential.

Adolescent↗
PubMedDate not supplied

Preembolization functional evaluation in brain arteriovenous malformations: the ability of superselective Amytal test to predict neurologic dysfunction before embolization.

PURPOSE: To describe the incidence of neurologic dysfunction following embolization of supratentorial AVMs, and to correlate findings with results of preembolization Amytal tests. MATERIALS AND METHODS: Data from 147 embolizations of supratentorial AVMs following Amytal tests in 30 awake patients were analyzed retrospectively. RESULTS: Of five embolizations done after a positive Amytal test, two were followed by neurologic complications. Eighty-two embolizations done as single embolizations immediately after a negative Amytal test were associated with no neurologic complications. The remaining embolizations were parts of multiple series of embolizations, each beginning with an Amytal test and followed by a number of embolizations without catheter movement or repeat Amytal testing. Since any prior embolization in the series might reduce the sump effect of the AVM, embolic agent delivered later in the series could potentially reach functional brain tissue not fully tested by the Amytal test. Therefore, repeat embolizations (not immediately preceded by an Amytal test) were considered separately. In 60 repeat embolizations, six (10%) were associated with some neurologic complication. CONCLUSIONS: Repeat Amytal testing might detect the loss of sump effect as the AVM is embolized. We conclude that use of data from superselective Amytal tests adds to the safety of AVM embolizations and that repeat Amytal testing potentially could be valuable when serial embolization of a vessel is planned.

Adolescent↗
PubMedDate not supplied

Intravascular microcatheter pressure monitoring: experimental results and early clinical evaluation.

With the use of Tracker and Balt microcatheter systems, intravascular pressure measurements were obtained in an experimental animal model, establishing the reliability of mean blood pressure measurements from these microcatheter systems. In the experimental model, selective occlusion of branches of the external carotid artery with simultaneous pressure measurements showed significant and reproducible changes in intravascular pressures. Also, pharmacologic manipulation of the blood pressure with simultaneous microcatheter and 6-French catheter recordings demonstrated an accurate and linear response of the microcatheter systems to mean blood pressure as it varied from 30 to 130 mm Hg. Preliminary results in humans with vascular malformations yielded similar results. We studied two cases of brain arteriovenous malformations (AVMs), one sigmoid-transverse sinus dural AVM, and one brain arteriovenous fistula (AVF). In these four cases the pressure dropped substantially, approaching the level of the shunt. In the case of the brain AVF, pressures rose in the same vessel after embolization. In the case of the dural AVM, correlation of the venous pouch pressures and the angiographic appearance indicated that shunting was no longer present when the venous and arterial pressures equalized. This system can be of substantial benefit in the evaluation and therapy of these lesions, and may increase our understanding of the physiology of vascular malformations.

Animals↗
PubMedDate not supplied

[Antinuclear antibodies and PHA response in rheumatoid arthritis].

We have studied the in vitro PHA response of two groups of rheumatoid arthritis patients differing only in the presence or absence of antinuclear antibodies. The response was depressed in positive patients and normal in negative patients. Differences in peripheral blood mononuclear cell sub-populations or lymphocytotoxic antibodies do not seem to explain this observation. Simple antinuclear antibody screening could serve as a simple method to identify a sub-group of immunodepressed rheumatoid patients as potential candidates for immunostimulating therapy.

Antibodies, Antinuclear↗