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Biomedical subjects

P Simard

Publications and source records attributed to P Simard.

At least 37 records · Page 2Linked to original sources
PubMed1987

Influence of growth medium and supplement on growth of Haemophilus influenzae and on antibacterial activity of several antibiotics.

In the present study, five non-beta-lactamase- and five beta-lactamase-producing strains of Haemophilus influenzae were used to determine whether three different growth media, Mueller-Hinton broth and agar, brain heart infusion broth and agar, and tryptic soy broth and agar, and their added supplements (0.2% hemin-0.1% IsoVitaleX, 1% hemin-1% IsoVitaleX, 2% sheep blood, 10% Fildes enrichment, 5% Fildes enrichment, 1% supplement B, 5% horse erythrocytes, and 2% hemoglobin-1% IsoVitaleX) would influence the growth rate of this microorganism and the antibacterial activity of eight antibiotics, including ampicillin, tetracycline, chloramphenicol, gentamicin, cefamandole, erythromycin, trimethoprim-sulfamethoxazole (TMP-SMX), and cefoperazone. The growth curve studies were carried out with an initial inoculum of 10(4) bacteria per ml, and MICs were determined with an inoculum of 5 X 10(5) microorganisms. Mueller-Hinton broth, brain heart infusion broth, and tryptic soy broth enriched with 5% Fildes resulted in a maximal growth of more than 10(8) CFU/ml at 24 h. When 10% Fildes or 2% sheep blood was added as enrichment to Mueller-Hinton broth, a considerable reduction in the growth rate of H. influenzae strains resulted (P less than 0.01). Significant variations in MICs (P less than 0.01) were observed with chloramphenicol, TMP-SMX, erythromycin, and cefoperazone when brain heart infusion agar, Mueller-Hinton agar, or tryptic soy agar was used. Chloramphenicol, gentamicin, erythromycin, and TMP-SMX were all affected by the different enrichments added to Mueller-Hinton agar. MICs were in general higher with 5% Fildes enrichment and lower with 1% supplement B. Cefoperazone was the only drug which exhibited a lower MIC in 5% Fildes enrichment for ampicillin-resistant H. influenzae strains.

Ampicillin↗
PubMed1986

Influence of three modes of administration on the penetration of latamoxef into interstitial fluid and fibrin clots and its in-vivo activity against Haemophilus influenzae.

The extravascular penetration and bactericidal activity of latamoxef against beta-lactamase positive Haemophilus influenzae were studied in a rabbit model. All groups of animals received over 24 h an identical dose of 100 mg/kg of latamoxef given by three different intravenous modes of administration including a single large injection of 100 mg/kg, four 25 mg/kg intermittent injections every 6 h, and a continuous infusion of 100 mg/kg over 24 h. A single large injection resulted in significantly higher peak levels and higher initial area under the curve of concentrations of drug in serum, interstitial fluid, and fibrin clots than other modes of administration. Continuous infusion resulted in an accumulation of drug in clots which rose from 1.0 microgram/g at 4 h to 4.9 micrograms/g at 24 h (P value less than 0.01). The rate of killing of H. influenzae imbedded in fibrin clots was greatly influenced by the different modes of therapy. Even though all regimens resulted in peak concentrations which were more than 80 times the MIC (0.03 mg/l) in the fibrin clots, rapid killing (from 10(7) to less than 10(2) micro-organisms per g of clots in less than 6 h) was only observed with a single bolus. Continuous infusion and intermittent injections of latamoxef resulted in limited in-vivo bactericidal activity. Large doses of latamoxef given at long intervals may be more effective than intermittent dosing or continuous infusion.

Animals↗
PubMed1986

Isolation, purification and culture of Sertoli cells from immature piglet testes.

Several studies suggest a role of Sertoli cells in the control of Leydig cell steroidogenesis. In order to verify this hypothesis, we have developed a system for the purification of pig Sertoli cells. These cells were then characterized by their morphological appearance in light and electron microscopy, their ability to bind [125I]follicle stimulating hormone (FSH) and their functional capacity as evaluated by adenosine 3',5' monophosphate (cAMP) accumulation and lactate production when in primary culture under basal and FSH-stimulated conditions. Crude Sertoli cell suspensions from immature porcine testes were fractionated on discontinuous Percoll gradients (densities 1.025, 1.039, 1.055, 1.080 g/ml). Highly purified Sertoli cells were contained in the second band (d: 1.039) generated on the gradient. These cells demonstrated morphological and functional integrity as evidenced by binding specifically [125I] FSH and by responding to FSH stimulation (by an increased production of cAMP and lactate after 3 days in primary culture), but not to human chorionic gonadotrophin (hCG). This preparation represents a useful model for the study of Sertoli cell functions and their interation with Leydig cells in the regulation of testicular steroidogenesis.

Animals↗
PubMed1985

[Bronchogenic cysts of the mediastinum in children. Apropos of 14 cases].

Fourteen children, aged from 2 months to 14 years, underwent surgical excision of a bronchogenic cyst in the mediastinum. Nine of these children were asymptomatic and the finding of the tumor was purely accidental. Retrotracheal and subcarinal localizations were more often symptomatic but their visualization on standard chest roentgenograms was sometimes difficult. An oesophagogram was helpful for the diagnosis in those circumstances. No postoperative complication occurred in our series.

Adolescent↗
PubMed1984

Intra-arterial infusion chemotherapy in rectal cancer.

Chemotherapy by intra-arterial infusion, using mitomycin C and 5-fluorouracil, was administered to six patients with cancer of the rectum. In three patients who presented initially with an inoperable rectal tumour, medication was infused through the inferior mesenteric artery. Tumour regression was documented in all three, allowing subsequent resection in two. Of three other patients with locally recurrent rectal cancer, none showed tumour regression after infusion, but two experienced substantial relief of perineal pain, with improvement in the quality of life. Unexpected complications occurred in the form of a reversible ischemic colitis in two patients and an arterioenteric fistula in a third.

Aged↗
PubMed1982

[Pleural mesothelioma: 3 developmental forms].

In the medical literature, there have been fewer reports on benign pleural mesotheliomas than on their malignant counterparts. We have reviewed the clinical, radiological and pathological features of mesotheliomas seen at the Hôtel-Dieu in Montreal over the past ten years. This experience leads us to postulate that there are three types of mesothelioma. The malignant form is often typical. Pedunculated lesions most often prove to be asymptomatic and benign. However, we have identified an intermediate category where the definitive nature of the mesothelioma could only be established after long term follow-up of the biological behaviour of the tumor.

Adult↗
PubMed1981

Limited in vitro activity of cefamandole against 100 beta-lactamase- and non-beta-lactamase-producing Haemophilus influenzae strains: comparison of moxalactam, chloramphenicol, and ampicillin.

In the present study, the minimal inhibitory concentrations and minimal bactericidal concentrations of moxalactam, cefamandole lithium, ampicillin, and chloramphenicol were determined, both in broth and on solid medium, against 75 non-beta-lactamase-producing and 25 beta-lactamase-producing strains of Haemophilus influenzae. Most of the 75 strains were inhibited or killed by 2 microgram or less of ampicillin, chloramphenicol, or moxalactam per ml, but cefamandole exhibited poor bactericidal activity against 11 non-beta-lactamase-producing strains, of which 9 were non-type B H. influenzae. Most of the 25 beta-lactamase-producing H. influenzae were resistant to 128 microgram of ampicillin per ml. Both moxalactam and chloramphenicol, which had minimal inhibitory concentrations of less than 0.25 and 2 microgram/ml, respectively, were more active than cefamandole, which had a minimal inhibitory concentration ranging from 2 to greater than or equal to 128 microgram/ml.

Ampicillin↗