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Biomedical subjects

B Lefebvre

Publications and source records attributed to B Lefebvre.

At least 37 records · Page 2Linked to original sources
PubMed1993

Stabilization of oversaturated aqueous solutions of deltamethrin, a highly lipophilic molecule.

The stability of oversaturated solutions of the highly lipophilic molecule deltamethrin under the conditions of continuous agitation and oxygenation by air bubble flow in a toxicologic test on fish embryos was studied. In polyethylene, glass, and Teflon containers, the 24-hr adsorption rate of 1 mg/l solutions was over 80%. Improvement by Sharon and Solomon's PEG-glass pretreatment did not exceed a small percentage. After agarose precoating, the adsorption rate in the glass or polyethylene containers was reduced to about 20%. The stabilizing effect of precoating agarose containers diminished with the concentration of the solution.

Adsorption↗
PubMed1990

Development of an expert system for bacterial identification: study of a prototype for identifying beta-galactosidase positive enterobacteria.

A prototype of an expert system for the identification of beta-galactosidase positive Enterobacteriaceae has been developed, for use with the API 20 EC kit. The system is implemented in Prolog on an IBM PC AT with 640 K of central memory and 20 megabytes of secondary memory. Its objectives are to highlight errors that can occur when the kit is in use. It can indicate the presence of new groups or species and give advice or suggest additional tests for the differentiation of the new species from those included in the kit.

Enterobacteriaceae↗
PubMed1986

A reproducible radionuclide procedure for measurement of cerebrospinal fluid shunt flow.

A radionuclide technique was developed to obtain reproducible measurements of cerebrospinal fluid flow in Rickham-Holter type shunt systems. In attempting to reproduce previously described radionuclide procedures, we found that different flow rate measurements can be obtained simply by changing the radiotracer injection technique or the method of analysis of the time activity curves which are generated. The importance of these technical pitfalls cannot be over-emphasized, since there is no gold standard to evaluate cerebrospinal fluid flow in vivo. An experimental model with a calibrated Harvard pump and a shunt system filled with normal saline was constructed. Aliquots of 500 microCi of pertechnetate in 0.05 ml of saline were injected serially into the center of Rickham reservoir using a size 28 needle. Time-activity curves were obtained after waiting five min to reach equilibrium, and standard curves of radiotracer clearance vs actual flow for each system used clinically in our institution were generated. In addition, a technique to quantify and thus correct for the small but significant leak of radiotracer which occurs at the site of injection in the reservoir is described. Excellent correlation was obtained between our results and the clinical and radiological findings in a preliminary clinical evaluation.

Cerebrospinal Fluid↗
PubMed1986

Vinblastine, adriamycin, and cyclophosphamide in the treatment of adenocarcinoma of the breast.

Thirty-two stage IV patients and one stage III patient with evaluable adenocarcinoma of the breast received treatment with vinblastine, adriamycin, and cyclophosphamide. One patient was unevaluable because of early death. Twenty-two of 32 patients (69%) achieved complete or partial remissions and seven (22%) stabilized, including two (6%) minor responses. One of the three (9%) patients failing treatment had had extensive prior chemotherapy. Five of seven patients over the age of 70 years achieved partial remissions. A sixth had a minor response. Three of five performance status 3 and one of two performance status 4 patients responded. Overall response rate (p less than 0.01) and complete remission rate (p less than 0.05) were greatest in soft tissue disease. Granulocytopenia was dose-limiting, and recommended starting doses are vinblastine 4 mg/m2, adriamycin 40 mg/m2, and cyclophosphamide 400 mg/m2. These doses produce granulocytopenia in the majority of patients, but recovery is rapid. Overall, this is a well-tolerated regimen comparable in efficacy to other adriamycin-containing combinations. Use of standard white blood count criteria instead of granulocyte criteria for determining dose alterations and time of retreatment would have resulted in markedly excessive dose reductions and treatment delays and in a marked reduction in permitted dose escalations. This could potentially have reduced the response rate.

Adenocarcinoma↗
PubMed1986

Neurotoxicity and efficacy of combined vinca alkaloids in breast cancer.

We treated 17 patients with metastatic breast cancer with the four-drug combination of vincristine (0.5-1.0 mg), vinblastine (4 mg/m2), doxorubicin (40 mg/m2), and cyclophosphamide (400 mg/m2). The two vinca alkaloids appeared to be synergistic in causing acute, reversible neurotoxicity, manifested primarily as diffuse pains involving one or more of jaws, limbs (particularly joints), chest, and abdomen. The response rate of 70% was no higher than that noted previously with a regimen identical to this one except for the exclusion of vincristine. Further studies of combined vinca alkaloids are not recommended in the treatment of breast cancer.

Adult↗
PubMed1986

[Necrotizing fasciitis and parotitis. Apropos of a case].

A rare lesion, but one particularly serious because of its evolution, necrotizing fasciitis must be treated surgically by wide debridement extending if necessary to the aponeurosis, even if the affection involves the face. A case with combined parotiditis and necrotizing fasciitis is used as a basis for review of the affection.

Aged↗
PubMed1985

Mitomycin-C plus metronidazole in advanced carcinoma of the breast.

Twenty-seven patients with metastatic adenocarcinoma of the breast refractory to other chemotherapy were treated with mitomycin-C plus metronidazole. The mitomycin-C dose was 15-20 mg/m2 I.V. repeated every 6-9 weeks. Metronidazole 1.5 g/m2 was given p.o. 12 hr and 1 hr before mitomycin-C and again 6 hr and 24 hr after mitomycin-C. Partial remissions were noted in 4 of 24 (17%) evaluable patients. Good performance status patients who were lightly pretreated, unresponsive to prior chemotherapy, and estrogen receptor negative were most likely to respond, and further studies are indicated in this subgroup of patients. Hematological toxicity was similar to that anticipated with mitomycin-C alone. Gastrointestinal toxicity was probably increased. Three probable and 2 possible cases of pulmonary toxicity were seen. It is unclear whether the incidence of mitomycin-C pulmonary toxicity was increased by the metronidazole.

Adenocarcinoma↗
PubMed1984

A randomized comparison of cyclophosphamide-mitoxantrone-5-fluorouracil v cyclophosphamide-doxorubicin-5-fluorouracil in advanced breast cancer: preliminary observations.

Forty-four patients with measurable metastatic breast cancer have been entered in a randomized study comparing mitoxantrone to doxorubicin as a component of front-line combination chemotherapy. Patients were stratified according to whether or not they had previously received adjuvant chemotherapy. Initial doses of cyclophosphamide and 5-fluorouracil were 500 mg/m2 for both regimens, with either mitoxantrone, 10 mg/m2, or doxorubicin, 50 mg/m2. All drugs were given on day 1 only, with treatments repeated every 3 weeks. Doses were adjusted according to blood count nadirs. Responses have been observed in both of the treatment groups, though it is too early to determine the relative efficacy of the two regimens. Toxicity was comparable on the two treatment regimens except that far less alopecia and stomatitis were associated with the mitoxantrone therapy. No congestive heart failure has been seen. The combination of cyclophosphamide-mitoxantrone-5-fluorouracil is reasonably well tolerated, with myelosuppression being dose limiting. In both treatment groups of this study, reliance on the leucocyte count, rather than the granulocyte count, as a basis for dose alteration or treatment delay would lead to excessive dose reductions, many fewer dose escalations, and much more treatment delay.

Anthraquinones↗
PubMed1983

Demonstration of a bronchobiliary fistula by 99mTc-HIDA cholescintigraphy.

A case of bronchobiliary fistula diagnosed by 99mTc-HIDA cholescintigraphy is presented. The fistula caused by a stenosing tumor of the left hepatic duct would probably have been missed without the use of delayed views and body fluids counting which increased the specificity of scintigraphic findings.

Bile Duct Neoplasms↗
PubMed1982

Antigenic variability between Candida albicans blastospores isolated from healthy subjects and patients with Candida infection.

Blastospores of 10 strains of C. albicans isolated from patients were compared with 10 strains from healthy subjects for their ability to detect antibodies by indirect immunofluorescence, with sera from the same patients and healthy subjects. Strains from patients were significantly more reactive with sera from patients than were strains from healthy individuals, but both groups of strains were equally reactive with sera from healthy subjects. These preliminary results indicate that the antigenic structure of C. albicans is not stable: there may be blastospore antigens that are qualitatively or quantitatively variable with the pathogenic behaviour of strains in vivo.

Antibodies, Fungal↗
PubMed1982

[Circular pharyngo-laryngectomy: reconstruction by free jejunal transplant and vascular microanastomoses in a single stage. 4 cases].

In a certain number of cases, extensive carcinomas of the hypopharynx require total pharyngeal resection, circular, and hence the restoration of continuity by a plastic procedure. Amongst the numerous procedures used (tubular flaps, substitution using a hollow organ), the authors opted for the use of free jejunal transplant with vascular microanastomoses in a single stage. Four cases very different in terms of their indications are reported. The postoperative course was in general very uncomplicated and characterised by the absence of either abdominal or pharyngeal infection. Swallowing became possible on about the 14th day. Vascular permeability was confirmed by arteriography in three cases and was felt to be satisfactory. This is, however, major surgery with a long operation (between 6 and 10 hours) and which at best requires the cooperation of two teams of surgeons. Indications should be considered with caution and in the present study involved only cases of widely extended pharyngeal carcinomas, with the exclusion of oesophageal involvement going beyond the pharyngo-oesophageal sphincter.

Aged↗
PubMed1981

[Taxonomic study of enterobacteria belonging or related to Escherichia coli species].

Phenetic (numerical analysis) and genetic (DNA-DNA hybridization) studies were carried out on strains belonging or related to the species Escherichia coli. They have shown the diversity of its phenotypes, by the presence of plasmidic characters (citrate+, urease+, H2S+, tetrathionate reductase+, raffinose+, and saccharose+). New strains related phenetically to E. coli are also individualized. They showed less than 30% DNA relatedness with E. coli. A new definition of E. coli is presented.

Bacteriological Techniques↗