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Biomedical subjects

J Bonnet

Publications and source records attributed to J Bonnet.

At least 19 recordsLinked to original sources
PubMed1992

Preparation and microscopic visualization of multicolor luminescent immunophosphors.

The preparation of charge-stabilized suspensions of small phosphor particles (0.1-0.3 micron) and their coupling with antibodies to immunoreactive conjugates is described. Phosphor particles consisting of yttriumoxisulfide activated with europium served as a model system in the evaluation of the stabilizing properties of several polycarboxylic acids. The optimal reagents were then applied to other phosphors which differ in spectral characteristics as well as in luminescence lifetime. These phosphors were ground to a size of 0.1-0.3 micron and proteins or other macromolecules were adsorbed to the phosphor particles to prepare conjugates of different physico-chemical properties. A time-resolved microscope, suitable for real time visualization of the time-delayed luminescence of the immunophosphors by the human eye, is described in detail. Since most phosphors require excitation with far UV light, a special fluorescence microscope allowing far UV excitation was developed for conventional visualization of the luminescence emitted by the phosphor. The possibility of multiple color labeling using various phosphor conjugates was demonstrated in a model system consisting of haptenized latex beads.

Adsorption↗
PubMed1992

Biological risk factors for sudden death in patients with coronary artery disease and without heart failure.

In a study of biological risk factors for sudden death in patients with coronary artery disease, 320 patients were, prospectively, recruited and followed-up over two years. None of the patients had heart failure or recent myocardial infarction. The following variables were recorded: previous acute myocardial infarction, hypertension, smoking habits, ventricular arrhythmia; the angiographic variables included: left ventricular ejection fraction, Jenkins' and mean atherosclerotic scores; lipid profile: cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, apolipoproteins Al and B; hemostatic profile: fibrinogen, fibrinopeptide A, antithrombin III, factor VIII antigen, factor VIII coagulant, protein C, plasminogen, alpha 2-antiplasmin, euglobulin clot lysis time and tissue plasminogen activator before and after venous occlusion, tissue plasminogen activator inhibitor, platelet factor 4, beta-thromboglobulin. During the follow-up period, 12 of the patients died suddenly. In these patients, ejection fraction was lower: 49 +/- 16% versus 61 +/- 14% for the other patients (P less than 0.02), fibrinogen higher: 3.9 +/- 0.8 g/l versus 3.5 +/- 0.8 for the living patients (P less than 0.05) and protein C lower: 89 +/- 39% versus 111 +/- 39% (P = 0.06) for the other patients. In multivariate analysis: lower ejection fraction (P less than 0.008), older age (P less than 0.03) and lower protein C (P less than 0.01) were correlated with sudden death. Among the patients with coronary artery disease, the raised fibrinogen and the decreased protein C appeared to be risk factors for sudden cardiac death. These alterations reflected a prothrombotic state which might increase the ischemic risk, due to an acute thrombosis, leading to the fatal ventricular arrhythmia. Determination of these hemostatic variables might be a useful adjunct for assessment of the vital prognosis of patients with coronary artery disease, especially the risk of sudden death in addition to other known clinical, electrocardiographic, hemodynamic risk factors. This would also guide both the instigation of complementary investigations and appropriate therapy in such high risk group of patients.

Aged↗
PubMed1992

Iridium-192 interstitial therapy for squamous cell carcinoma of the penis.

From February 1971 through February 1989, 51 patients with biopsy proven epidermoid carcinoma of the penis were treated with interstitial therapy (Iridium 192). The breakdown according to the stage was T1s = 3, T1 = 14, T2 = 28, T3 = 6, N0 = 43, N1 = 7, N2 = 1. The dose ranged from 50 to 65 Gy (mean: 60 Gy). Patients without clinical nodal involvement received no treatment to the nodes. Stage N1 and N2 patients had surgery and external irradiation to the inguinal and iliac nodes. Six of fifty-one (12%) patients developed nodal and/or metastatic disease following therapy. Five of six presented initially with clinical nodal involvement. Seven of fifty-one (14%) developed local recurrence only, requiring surgery (four partial penectomies, three total penectomies). Six of these seven patients are alive and free of disease with a mean follow-up of 5.5 years. Nine of thirty eight (23%) patients with local control developed local necrosis. The treatment consisted of local excision (one patient), partial amputation (six patients) or total amputation (two patients). Partial urethral stenosis was noted in 17/38 (45%) of the patients. Foreskin sclerosis occurred in 3/38 (8%) uncircumcised patients. Interstitial irradiation for penile carcinoma provided effective local control rates, especially for T1-T2 patients (91%). Local failures could be treated successfully with surgery. Complications could be treated conservatively in most patients. Local control with penile conservation was achieved in 67% of all patients and 75% of patients with T1-T2 disease.

Adult↗
PubMed1992

P0 protein in normal, trembler heterozygous/homozygous mice during active PNS myelination.

The quantification of P0 protein has been currently used to measure the myelination of the peripheral nervous system (PNS). Using immunological techniques, we show that, as early as postnatal day 8, the P0 content of mice homozygous and heterozygous for the Trembler mutation, represent respectively one tenth and half of the normal values. Thus, although the Trembler mutation is dominant, the myelination defect observed in heterozygous Trembler mice is more pronounced in the homozygous Trembler mice. This gene dosage effect should be taken into account when a molecular model of the Trembler mutation will be proposed.

Animals↗
PubMed1992

Expression of the PMP-22 gene in Trembler mutant mice: comparison with the other myelin protein genes.

The Trembler mouse suffers from a dominantly inherited autosomal mutation affecting the Schwann cell activities, which results in an abnormal myelination of the peripheral nervous system. Very recently, it has been shown that the mutation is in the PMP-22 gene. However, the level of expression of the mutated gene in trembler mice has not been studied. Therefore, we measured the steady-state levels of mRNA encoding PMP-22 in the sciatic nerve of normal and trembler mice, and we compared these results with the steady-state levels of mRNAs encoding the major peripheral nervous system myelin proteins. Our results show that all the myelin protein genes studied are affected by the trembler mutation but to a different extent, and that the PMP-22 gene is expressed at very low levels in the trembler nerve. This suggests that regulation of the expression of the PMP-22 gene is altered in the Trembler mutant.

Animals↗
PubMed1992

Evaluation of plasmatic leucocyte elastase levels in coronary artery disease.

Leucocyte elastase may be involved in the structural modification observed in the atherosclerotic process. Therefore, we tested the usefulness of leucocyte elastase plasma level determination as a marker for atherosclerosis. Plasma levels of elastase were determined by ELISA in 100 consecutive patients (mean age 56 +/- 9.8 years) admitted to hospital for coronary angiographic investigation of chest pain. Eighty-seven patients had evidence of atherosclerosis, and 13 patients had normal coronary vessels. No significant difference in leucocyte elastase was found between the 2 groups, nor was there any relationship between elastase levels and the severity of atherosclerosis. However, relationships between plasma leucocyte elastase levels and various lipid fractions (Apo AI, LDL) and daily tobacco consumption were found. Leucocyte elastase may thus play a role not only by direct modification of the vessel wall, but also indirectly via risk factors such as dyslipoproteinemia and leucocyte toxicity.

Coronary Angiography↗
PubMed1992

[The anticoagulant properties of the endothelium studied by the standard venous occlusion test].

Venous occlusion (VO) during which thrombin (Th) is postulated to be generated is routinely used for evaluation of fibrinolytic potential of endothelium (E). This study was performed to find out whether VO can also be used for assessment of anticoagulant function of E. VO was performed in 98 male patients (pts) with ischemic heart disease. Levels of protein C (PrC) which is related to Th binding by thrombomodulin and fibrinopeptide A (FpA)--a marker of presence of free Th--were determined together with some other factors of coagulation and fibrinolysis. Differences between pre- and postVO PrC levels fluctuated from -54.8% to +57.3%. According to reaction of PrC to VO pts were divided into 2 groups: 13 pts with increase or no change and 17 pts with decrease (consumption) of PrC. In pts without PrC consumption there was a significant increase in FpA. In pts with PrC consumption FpA was unchanged. In pts with PrC consumption exceeding its median value for this group (14%) PAI-1 antigen level fell significantly (-8.4 + 4%) during VO. Thus PrC consumption after VO indicates that TH is effectively removed from blood stream by endothelial factors. Absence of consumption of PrC is a sign of ineffective anticoagulant function of E. Increase in PrC level during VO in some pts may be due to its escape from tissue depot.

Adult↗
PubMed1991

[Cardiac lesions in Takayasu's disease. A case with initial pericarditis and tamponade].

The authors report the case of 21-year old female patient with a particular form of Takayasu's disease remarkable for its initial presentation and its cardiac and coronary lesions. The disease began with miscarriage at the 5th months of pregnancy, followed by acute pericarditis with tamponade. Subsequently, lesions of the aortic and mitral valves developed, while the myocardium became involved with left ventricular dilatation and hypokinesia confirmed by echocardiography and cineangiography. Coronary arteriography revealed large coronary aneurysms which are exceptional in this disease. This case prompted the authors to discuss the various cardiac lesions and the relationship of Takayasu's disease with pregnancy.

Adult↗
PubMed1991

Typing of Chlamydia trachomatis by restriction endonuclease analysis of the amplified major outer membrane protein gene.

A procedure was developed for characterization of Chlamydia trachomatis strains by using restriction endonuclease analysis of amplified genes of the major outer membrane protein (MOMP). Reference strains of the 15 serovars (A through K and L1 through L3) and clinical isolates were tested. The nucleotide sequences of the MOMP genes of each of the 15 serovars were arbitrarily constructed by using the sequences of the four variable domains known for each serovar and the constant domains of serovar L1. Computer analysis of these sequences indicated that two restriction digestions performed in parallel, one with AluI and the other with IIpaII, followed by HinfI and EcoRI, would allow the theoretical differentiation of 13 serovars. Serovars Ba and L1 presented the same theoretical restriction profile. Our typing method consisted of polymerase chain reaction amplification of a fragment of about 1,200 bp of the MOMP gene, followed by restriction endonuclease digestion with the aforementioned enzymes. From the 15 serovars, we obtained 14 different patterns; 13 profiles were serovar specific, while serovars B and Ba presented the same pattern. Application of this typing method to C. trachomatis strains isolated from clinical material gave the same results as the immunotyping method for 14 of 17 strains. Furthermore, restriction endonuclease analysis detected differences within a serovar. This method seems to be promising for epidemiological studies.

Bacterial Outer Membrane Proteins↗
PubMed1979

5 FU infusion with mitomycin-C vs. 5 FU infusion with methyl-CCNU in the treatment of advanced upper gastrointestinal cancer: a Southwest Oncology Group Study.

A randomized trial was conducted by the Southwest Oncology Group (SWOG) in advanced carcinoma of the stomach and pancreas. Patients were assigned to receive monthly 5-fluorouracil 96-hour continuous infusions with either bolus mitomycin-C or oral methyl-CCNU. Mitomycin-C and methyl-CCNU were administered every eight weeks. The 5 FU-mitomycin combination produced a 14% and 22% response rate in disseminated stomach and pancreatic carcinoma, respectively. The combination of infusion 5 FU and methyl-CCNU achieved responses in 9% and 5% of stomach and pancreatic tumors, respectively. There was no significant difference in survival between limbs for either tumor. Median survival in gastric carcinoma on the 5 FU-mitomycin regimen was 25 weeks vs. 18 weeks on the 5 FU-METHYL-CCNU arm. In pancreatic carcinoma median survival on the mitomycin limb was 19 weeks as compared to 17 weeks on the methyl-CCNU program. Leukopenia was greater for the first course on the mitomycin limb. Regression analysis demonstrated that performance status was the most important pretreatment characteristic for predicting survival in both tumors. Neither 5 FU infusion combination appears to significantly alter the dismal prognosis of advanced upper gastrointestinal neoplasms.

Antineoplastic Agents↗
PubMed1979

Lack of correlation between affinity of the tRNA for the aminoacyl-tRNA synthetase and aminoacylation capacity as studied with modified tRNAPhe.

The interactions of several modified yeast tRNAPhe [tRNAPhe lacking 7-methylguanine; a fragment comprising about 3/4 of the whole molecule: tRNAPhe (18--76); tRNAPhe (18--76) lacking 7-methylguanine] with yeast phenylalanyl-tRNA synthetase were studied. Upon excision of the 5'-quarter of the tRNAPhe molecule, the residual fragment still tightly binds to the synthetase, but can no longer by aminoacylated. Surprisingly, upon removal of the 7-methylguanine base at position 46 in this fragment, althought the affinity drops by a factor 10, a significant aminoacylation is restored. These results are discussed in terms of molecular flexibility and a model is proposed for tRNA-enzyme interaction, involving multisite recognition.

Amino Acyl-tRNA Synthetases↗
PubMed1979

An automated microscope for quantitative cytology combining television image analysis and stage scanning microphotometry.

This paper describes an automated microscope developed for operation in conjunction with the Leyden Television Analysis System. It features automated control of magnification, illumination, movement of scanning stages, and fine focus. These functions are controlled by means of a microcomputer. This enables a flexible design and relieves the supervising computer of simple but time consuming tasks. The combination of an automated microscope and Leyden Television Analysis System provides a powerful tool in quantitative cytological research. The flexible design permits other microscopic functions to be added with relatively little effort.

Computers↗
PubMed1978

5FU infusion with mitomycin-C versus 5 FU infusion with methyl-CCNU in the treatment of advanced colon cancer: a Southwest Oncology Group Study.

The Southwest Oncology Group (SWOG) in a randomized trial evaluated 5FU infusions in combination with either Mitomycin-C or Methyl-CCNU in patients with disseminated large bowel cancer. A response rate of 18% was noted on the 5FU-Mitomycin limb as compared to 16% on the Methyl-CCNU arm (p = .39). Median survival for all treated patients was 43 weeks on both arms. Myelosuppression was found to be more significant on the Mitomycin-C arm. Regression analysis demonstrated that performance status, sex, and primary site were significant pretreatment characteristics for predicting survival. The response rates associated with this burdensome method of 5FU administration in combination with either Mitomycin-C or Methyl-CCNU appear to offer little advantage over bolus 5FU alone.

Adenocarcinoma↗
PubMed1978

[Effects of small doses of gamma rays on gestation in mice].

Female mice were irradiated with 10 rads of 60Co gamma ray, 7 hours after mating. This low dose induces a decrease in implantation number, and alive foetus number and is followed by a lower number of corpora lutea. These results to seem to show an effect of gamma irradiation on ovary and embryonic development.

Animals↗
PubMed1977

A new type of cytocentrifuge, the valve-centrifuge.

A new type of cytocentrifuge has been developed in which the sedimentation process of the cells onto the slides is separated from the draining of the sedimentation fluid. This is realised by electrically controlled valves which can be closed and opened while the centrifuge is running. Sedimentation is carried out with closed valves, draining of adhering medium with open valves. The preparations, freed of adhering medium by the centrifugal force can be taken out and the cells can be fixed. Alternatively the valves can be closed again and fixative can be introduced through a central well, the cells still being under the influence of the centrifugal force. With subsequent draining of the fixative and introduction of washing and staining solutions through the central well, the whole process from sedimentation to staining can be carried out in the running centrifuge. The process seems well suited for complete automation. Using dilution series from a suspension of human buffy coat cells counted in a Buerker chamber, the cell counts in the centrifuge preparations showed virtually total recovery of cells, with no apparent selection or specific distribution of cell types. Draining of the sedimentation and fixative fluids at a slow rate was found to be vital for optimal recovery of cells. The morphology of different cell types sedimented on the slide was excellent. The flattening of nuclei thorugh gravity was studied by cytophotometry of Feulgen-stained leucocytes. The nuclear area of these cells was found to be approximately double that from cells in identically stained classical smears. With this type of valve-centrifuge a quantitative and unbiased recovery of uniformly spread and flattened cells on coverslips or slides may be obtained, thus making the procedure well suited to automated analysis based on cytophotometric principles and morphometric pattern recognition.

Animals↗