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Biomedical subjects

J A Gagnon

Publications and source records attributed to J A Gagnon.

18 recordsLinked to original sources

Bacterial decontamination of blood stem cell apheresis products.

High-dose chemotherapy using autologous bone marrow or mobilized blood as the source of stem cells for haematologic rescue, is being widely used for a variety of haematological malignancies and solid tumours. To collect sufficient numbers of haematopoietic stem cells for successful engraftment, standard apheresis procedures are performed. Newer techniques and refinements of the procedure allow using only 1 to 2 apheresis products (AP) for autografting. Bacterial contamination of the AP, although very rare, sometimes occurs and may lead to generalized infection in the recipient. The apheresis must be repeated, sometimes even including time-consuming and costly mobilization. At our institution, the patients' blood stem cells are usually mobilized with chemotherapy followed by daily s.c. haematopoietic growth factor injections or with growth factor alone. An apheresis machine is used for collection through a central venous line and the AP is routinely checked for bacterial contamination. Results are only available after the product has been processed and cryopreserved. In the last 5 years, we observed bacterial contamination in four of our AP. Therefore, we investigated the possibility of in vitro antibiotic decontamination. Using standard antibiograms, we determined the sensitivities of the contaminating bacteria. By incubating the products with the specific antibiotics at bactericidal concentrations, we were able to sterilize the probes from the contaminating bacteria. In the concurrently performed controls without the active substance, bacteria were still detectable. We conclude that in selected cases, in vitro decontamination using pretested antibiotics, may be a feasible, cost-effective, and easy alternative to performing additional apheresis procedures.

Anti-Bacterial Agents↗

Primary pulmonary hypertension associated with HIV infection.

A Haitian woman with the human immunodeficiency virus (HIV) presented with dyspnea, cough, fatigue and lower abdominal pain of recent onset. Clinical, radiologic and hemodynamic investigations demonstrated pulmonary hypertension. The patient died a few days later. The pathological findings were compatible with primary pulmonary hypertension. This case is similar to others that have been reported and indicates a possible link between HIV infection and rapidly progressive primary pulmonary hypertension.

Acquired Immunodeficiency Syndrome↗

Intrarenal kallikrein-kinin activity in acute renovascular hypertension in dogs.

The intrarenal kallikrein-kinin system was studied during the acute phase of renovascular hypertension induced by renal artery constriction and during teprotide inhibition of kininase II in the dog. Kallikrein-like activity measured by both kininogenase and esterolytic assays, was increased during renal artery constriction (p less than 0.5) and (p less than 0.01). The administration of teprotide resulted in a further increase of renal cortical kallikrein-like activity and inhibited kininase II activity (p less than 0.01). Following the inhibition of kininase II, the plasma concentration of kininogen was also significantly decreased (p less than 0.01). These results suggest that kininase II inhibition may increase levels of intrarenal and plasma kinins and that decreased degradation of kinin peptides may contribute significantly to the acute hypertensive effect of teprotide.

Animals↗

Plasma kinin levels in acute renovascular hypertension in dogs.

The role of kinins in the hypertensive response to acute renal artery constriction (RAC) was examined in the dog. RAC resulted in an increase in systemic arterial pressure (SAP) from 144 +/- 6 to 155 +/- 4 mm HG (p less than 0.05). Simultaneously, arterial plasma bradykinin decreased from 2.3 +/- 0.2 to 1.4 +/- 0.1 ng/ml (p greater than 0.01), while renal venous bradykinin remained unchanged (2.3 +/- 0.2 to 2.0 +/- 0.4 ng/ml, p greater than 0.05). At the same time urinary kallikrein decreased from 55 +/- 6 to 33 +/- 4 milliesterase units (mEU)/min (p less than 0.05), while urinary kinin decreased from 3.2 +/- 0.4 to 1.9 +/- 0.3 ng/min (p less than 0.05). There was a significant correlation between the decrease in arterial bradykinin and the rise in SAP induced by RAC (p less than 0.01). Administration of the dipeptidyl hydrolase inhibitor SQ20881 during RAC reduced angiotensin-converting enzyme levels from 578 +/- 86 to 10 +/- 0.0 mU/ml (p less than 0.005). There was an associated increase in arterial bradykinin (1.4 +/- 0.1 to 5.8 +/- 0.8 ng/ml, p less than 0.001), renal venous bradykinin (2.0 +/- 0.4 to 5.7 +/- 0.5 ng/ml, p less than 0.005), and urinary kinin (1.9 +/- 0.3 to 5.0 +/- 0.7 ng/min, p less than 0.01) in conjunction with return of SAP to control levels. Urinary kallikrein, however, remained depressed following SQ20881 (33 +/- 4 to 30 +/- 5 mEU/min, p greater than 0.05). These results suggest that (1) decreases in circulating BK may potentiate the vasoconstrictor effect of angiotensin II and contribute to the hypertension induced by RAC, and (2) urinary kallikrein is an unreliable marker of changes in plasma bradykinin in this model of hypertension.

Angiotensin II↗

[De novo appearance of a partial trisomy 1q in mosaic due to a 1;9 translocation].

A child with trisomy 1q24----qter is described. This syndrome is compared to other 1q partial trisomies. An association is proposed between these trisomic segments and the following phenotypic signs: microphtalmia, trigonocephaly, hypertrichosis, antimongoloid eye slants, anomalies of the biliary tract, and malformations of the central nervous system.

Abnormalities, Multiple↗

Influence of thiopental anesthesia on renal sodium and water excretion in the dog.

The influence of thiopental anesthesia on renal tubular sodium reabsorption was investigated in the well-trained dog. After administration of the anesthetic, renal sodium reabsorption was depressed, leading to the enhanced excretion of sodium and water. Associated with this response was a decrease in the plasma levels of epinephrine and norepinephrine. Neither renal hemodynamic functions nor the humoral factors, prostaglandin E, plasma renin activity, or arginine vasopressin appeared to be the major determinants of the natriuresis. These observations suggest that the administration of thiopental depresses renal sympathetic nerve activity, thereby diminishing the renal tubular transport of sodium.

Animals↗

Pyrogenic renal hyperemia: the role of prostaglandins.

The intravenous administration of triple typhoid vaccine to anesthetized dogs resulted in a significant increase in renal blood flow accompanied by a modest decline in systemic blood pressure. This renal hyperemia was associated with elevated renal secretory rates of renin and prostaglandin E and F. Measurements of the intracortical distribution of radiolabeled microspheres revealed a progressive decrease in outer cortical blood flow rates and a progressive increase in inner cortical flow rates. When meclofenamate, an inhibitor of prostaglandin synthetase, was administered concomitantly with triple typhoid vaccine renal hyperemia did not develop. The renal renin secretory rate increased modestly and intracortical renal blood flow was not redistributed. The increased renal blood flow after triple typhoid vaccine administration to unanesthetized dogs was also reversed by meclofenamate. The marked increase in prostaglandin secretion by the kidney during renal hyperemia following triple typhoid vaccine administration (pyrogen), and the effect of meclofenamate, is consonant with a role for increased renal synthesis and release of prostaglandins.

Animals↗

Autoimmune hemolytic anemia terminating seven years later in Hodgkin's disease.

A 64-year-old woman was treated during 7(1/2) years for an isolated AIHA by transfusions, prednisone and splenectomy. The autoantibody was a warm-type IgG with anti-e specificity. At autopsy, generalized Hodgkin's disease of mixed cellularity was found. Only 11 similar cases of hemolytic anemia preceding the development of Hodgkin's disease have been reported in the literature. This association suggests a possible underlying defect in the immune system of the host.

Anemia, Hemolytic, Autoimmune↗

Leasing: is it really the answer to your financing needs?

Leasing hospital equipment may not be the best method of financing such purchases. Early reimbursement agreements offered significant financial benefits to the leasing institution in terms of increased cash flow and additional cash reimbursement dollars. However, changes in the third-party reimbursement formula have partially eliminated the financial advantages of leasing. The author discusses the effect of these changes on leasing agreements, and why hospitals still lease, and answers some of the common assertions in support of leasing.

Costs and Cost Analysis↗