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Biomedical subjects

M Paquin

Publications and source records attributed to M Paquin.

9 recordsLinked to original sources
PubMed1989

Chronic B-cell lymphocytosis.

Persistent elevation of lymphocyte counts is usually associated with a malignant monoclonal lymphoproliferative disease. Over the last 8 years, amongst patients investigated in our center for undetermined persistent lymphocytosis, a diagnosis of malignant lymphoproliferation was excluded in 6 cases as studies of surface membrane immunoglobulin light chains showed that they presented a polyclonal expansion of their B-lymphocyte pool. All patients were young-to-middle aged women presenting peculiar immunohematologic findings characterized by 1) persistent (2-7 yr) elevation of lymphocyte counts (4-14 x 10(9)/l), 2) presence of characteristic binucleated B cells on peripheral blood smears, 3) a normal bone marrow histology, 4) a polyclonal increase of serum IgM with low-to-normal IgG and IgA levels. Histologic examination of the spleen in 2 patients and lymph nodes in 1 showed a benign follicular lymphoid hyperplasia. The evolution was benign in every case. We suggest that chronic polyclonal B-cell lymphocytosis is a distinct clinicopathologic entity that should not be confused with malignant lymphoproliferative disorders.

Adult↗
PubMed1988

Use of acetylcholine to measure total vascular pressure-volume relationship in dogs.

To define total vascular capacitance, we used acetylcholine to arrest the heart and measured mean circulatory filling pressure (MCFP) during controlled hemorrhage and volume loading in 12 splenectomized dogs after ganglion blockade with hexamethonium. We also examined the gross pathological and histological changes in the lungs. Controlled hemorrhage (n = 12) of 5 and 10 ml/kg decreased MCFP from 6.8 +/- 0.1 to 4.9 +/- 0.3 and 3.6 +/- 0.2 mmHg, respectively. Volume loading of 5 (n = 8) and 10 ml/kg (n = 4) increased MCFP to 9.3 +/- 0.2 and 12.1 +/- 0.1 mmHg, respectively. At MCFPs below 5 mmHg, the pressure (P)-volume (V) relationship was not linear [(P = P0ekV, where k is slope of ln (MCFP) vs. V, k = 0.061, R2 = 0.998]. At MCFPs between 5 and 12 mmHg, the pressure-volume relationship was linear (slope = 0.479 mmHg.ml-1.kg-1, R2 = 0.992) and total vascular compliance was 2.09 ml.mmHg-1.kg-1. There were no changes in heart rate, cardiac output, right atrial, pulmonary artery, and pulmonary artery wedge pressures when values at base line were compared with those measured 15 min after each arrest. There were no changes in arterial gas measurements or acid-base balance, and there was no evidence of atelectasis or interstitial or intra-alveolar edema. We conclude that the total body pressure-volume relationship in the presence of ganglion blockade had a nonlinear configuration. The use of acetylcholine to arrest the heart, four times with hexamethonium in reflex-blocked animals, did not result in changes in hemodynamics or pulmonary function.

Acetylcholine↗
PubMed1987

Pulmonary toxicity associated with fludarabine monophosphate.

Fludarabine monophosphate (FAMP), the 2-fluoro, 5' phosphate derivative of 9-beta-D-arabinofuranosyl adenine (ara-A), is a purine nucleoside antimetabolite presently undergoing clinical testing for the treatment of a variety of malignancies including lymphoproliferative disorders and acute leukemia. We report a case of diffuse interstitial pneumonitis during treatment of chronic lymphocytic leukemia with FAMP. This resolved quickly with high dose steroids, recurred with steroid withdrawal, and abated with further steroid therapy. To our knowledge, this is the first reported case of fludarabine monophosphate associated pulmonary toxicity.

Antimetabolites, Antineoplastic↗
PubMed1987

Monocyte-macrophage (M-M) functions in asymptomatic hemophiliacs and supertransfused thalassemics.

Patients suffering from acquired immune deficiency syndrome (AIDS) succumb to opportunistic infections due to a generalized failure of their cell-mediated immune defenses. The monocyte-macrophage (M-M) system plays an important role in host defense against viruses, protozoa, mycobacteria, and tumours, all potentially involved in the terminal stages of AIDS. We studied M-M functions in 55 asymptomatic hemophiliacs, 20 supertransfused thalassemics, and 9 von Willebrand's syndrome patients over a period of 17 months to establish the part played by chronic repeated blood component transfusions on the macrophage defense system. We found a significant impairment of chemotaxis in 24 out of 55 hemophiliacs, 13 out of 20 thalassemics, and 4 out of 9 von Willebrand's patients. In contrast, Candida pseudotropicalis killing was markedly increased in all 3 patient groups, while Candida phagocytosis was most significantly diminished in thalassemics. Fc-receptor-dependent erythrophagocytosis showed wide variations in all patients, with a significant decrease only in thalassemics. Phorbol ester-activated nitroblue tetrazolium (NBT) reduction to formazan was normal in most cases, but background spontaneous NBT was often much higher than in the controls. Monocyte adhesion to plastic appeared impaired in hemophiliacs and von Willebrand's Syndrome patients, yet was of no statistical significance. It thus appears that continuous, repeated blood component transfusions cause an alteration of M-M functions. This may be either due to chronic, recurrent antigenic stimulation by foreign proteins transfused, or oncogenic and known immune suppressive viruses, like cytomegalovirus, Epstein-Barr virus, hepatitis, and human T cell lymphotropic virus III. This in turn may increase susceptibility to AIDS.

Adolescent↗
PubMed1986

Total vascular pressure-volume relationship in conscious rats with chronic heart failure.

To define the changes in the venous circulation in chronic left ventricular (LV) failure, we measured the mean circulatory filling pressure (MCFP), blood volume, and effective vascular compliance in conscious rats with heart failure, 3 wk after coronary ligation. Rats with myocardial infarction and LV end-diastolic pressure (EDP) greater than 15 mmHg were considered to have chronic heart failure. Rats with chronic heart failure (n = 11) showed an increase (P less than 0.001) in LV EDP to 24 +/- 2 mmHg compared with 6 +/- 1 mmHg in sham-operated (n = 9) and 7 +/- 1 mmHg in normal (n = 6) rats. In the rats with chronic heart failure the MCFP was increased to 9.9 +/- 0.2 mmHg (P less than 0.001) compared with 7.6 +/- 0.2 mmHg in the sham-operated and 7.7 +/- 0.2 mmHg in the normal rats. Effective vascular compliance was determined from MCFP-blood volume curves. In rats with chronic heart failure, the effective vascular compliance was decreased to 2.40 +/- 0.08 ml X mmHg-1 X kg-1 from 3.34 +/- 0.16 in sham-operated rats and 3.35 +/- 0.22 ml X mmHg-1 X kg-1 in normal rats. The blood volume and the unstressed vascular volume of the rats with chronic heart failure were not statistically different from the sham-operated rats. These results suggest that venous capacitance is decreased in chronic heart failure, due to a decrease in effective vascular compliance with no significant change in unstressed vascular volume. Hexamethonium chloride did not alter the effective vascular compliance of the rats with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Societal and ethical considerations of artificial hearts.

The present state of artificial heart research and development is analyzed in light of public perceptions affected by accounts of the experiences of those who received the Jarvik-7. On the assumption that research will continue, it is argued that the therapeutic goals of the artificial heart can be realized, and funding be obtained, only in an atmosphere of positive publicity. To this end, formation of an association of companies involved in artificial heart R & D is recommended. Such a group would articulate voluntary standards and produce reports of advances in the field. Artificial hearts, it is noted in conclusion, have been effective as temporary assist devices in patients destined to receive heart transplants.

Ethics, Medical↗
PubMed1986

Immunologic complexity of lymphoblastic lymphoma.

Twelve patients with a histologic diagnosis of lymphoblastic lymphoma (LBL) were studied immunologically using the methodologic refinement of comparative serial section immunochemistry. By this means, we demonstrate complex LBL phenotypic profiles, revealing 3 major immunologic subtypes: immature T cell, 7 cases; intermediate or mature T cell, 3 cases; immature B cell (pre-pre-B), 2 cases. This phenotypic diversity challenges the basic belief that all LBL are the same. Our immature T-cell cases with frequent simultaneous Leu 2/3/6/9/CALLA/Tdt expression correspond to cortical thymic phenotypes; our mature T-cell phenotypes with Leu 9/la expression and absent L6/Tdt correspond either to medullary thymocytes or post-thymic T cells; our pre-pre-B phenotypes with simultaneous Tdt/CALLA/B4 expression correspond to common acute lymphocytic leukemia (ALL) phenotypes. Mature T-LBL phenotypes are similar to "novel" peripheral T-cell lymphoma phenotypes. Scant or absent Tdt expression in mature LBL is not an isolated antigenic change but a complete phenotypic profile difference from immature T-LBL. The major T- and B-cell phenotypes of LBL might have therapeutic significance. Treatment among LBL phenotypes may need to vary as with acute lymphocytic leukemia phenotypes. Further study is needed; in the meantime, comparative serial section immunotyping promises substantial utility in revealing the immunologic complexity of the lymphomas.

Adolescent↗