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Biomedical subjects

C Marchal

Publications and source records attributed to C Marchal.

At least 127 records · Page 7Linked to original sources
PubMed1985

[Medium-term results of 200 consecutive systematic operations for revascularization of the anterior interventricular artery by the internal mammary artery].

This study presents the preliminary results of systematic revascularisation of the left anterior descending (LAD) by the internal mammary (IM) artery. Between 1981 and 1983, 200 IM bypass procedures were performed (88.5% of bypassed LAD arteries during the same period). With experience, the contraindications of IM bypass surgery progressively decreased (none in the latter 100 cases). The IM bypass grafting was an isolated procedure in 35% of cases and associated with one or more saphenous vein (SV) bypass grafts in 64.5% of cases with an average of 1.9 grafts per patient. The surgical results were better than those of SV bypass grafting alone in the period 1978-1980 with a mortality of 2.5% and a perioperative infarction rate of 2.5% compared to 4.3% and 7% respectively. The medium term results (average follow up 2.5 years) show that more patients undergoing IM bypass surgery were asymptomatic (75%) than those undergoing SV bypass (46%). However, the patients operated more recently by IM bypass benefitted from the latest technical advances in bypass surgery. An unselected sample of 55 volunteers (out of 90 recalled patients) underwent angiography at 1 year. The patency rate was 93% with a very satisfactory angiographic appearance of the graft in nearly all patients suggesting the likelihood of a good long term result. It was possible to demonstrate graft patency by Doppler ultrasound and digitised intravenous angiography in some cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1984

[Development of urea, creatinine and creatinine clearance as a function of age and sex].

Serum urea and creatinine concentrations were determined in 150 healthy subjects. The formula of Cockcroft and Gault was used in order to calculate creatinine clearance. Such estimation of creatinine clearance is widely used as a parameter for individualization of dosage of drugs secreted primary via the kidneys. The effects of age and sex were then assessed on serum urea, serum creatinine and on creatinine clearance.

Adult↗
PubMed1984

[Validation of quantitative and qualitative data of real-time carotid echotomography in comparison with standard Doppler tests, arteriography and anatomopathology. On 59 carotid endarterectomies].

Findings on ultrasound, arteriography and pathology examinations were compared in 49 patients undergoing 59 carotid endarterectomies between December 1981 and April 1983. Carotid artery lesions were investigated routinely by cervical Doppler, high resolution rapid ultrasound and either direct or more usually venous arteriography (with photographic subtractions). Postoperative endarterectomy specimens were examined to determine the exact degree of stenosis, and also qualitatively (gross pathology and histology of ulcerations and thromboses, the biochemical nature of the plaques, etc.). With respect to detection, that is demonstration of the existence or not of an atheromatous lesion, the ultrasonographic findings could always (100% of cases) be correlated with pathology data. Qualitative analysis of atheromatous lesions showed certain to be diagnosed with ease: calcified, fibrous or chondroid and lipidic plaques, while those complicated by hemorrhage, ulceration or mural thrombosis were less constantly diagnosed by ultrasound imaging. Occlusive plaques were easily detected, while recent intraluminal thrombosis was more difficult to diagnose by ultrasound alone. In this case the combined use of Doppler is a valuable aid, and is a routine procedure, in fact, in the department. Results of quantitative analysis showed good correlation between ultrasound and pathology findings in 79.7% of cases (insufficient in 20.3%). However, if ultrasonography is combined with other ultrasound methods of examination (standard Doppler and spectral analysis of Doppler) correlation is of the order of 95%, close to morphological data supplied by arteriography, with in addition a functional and qualitative approach not possible with arteriography alone.

Aged↗
PubMed1984

Tumor uptake of high and low molecular weight fractions from 67Ga-citrate labelled blood plasma.

Blood plasma from tumor-bearing rats was incubated with 67Ga-citrate, and two fractions of high molecular weight (proteins) and low molecular weight were isolated by dialysis and by gel-filtration chromatography. Both fractions showed a different in vivo uptake by DS-sarcoma-bearing animals, the high molecular weight fraction being accumulated to a lesser extent. Compared to 67Ga-citrate the low molecular weight fraction showed a different uptake which for most tissues was significatively higher. This behavior suggests the presence of 67Ga in chemical forms other than citrate in the low molecular weight fraction. The lower uptake of the blood protein fraction is discussed.

Animals↗
PubMed1983

Genetic study of a membrane protein: DNA sequence alterations due to 17 lamB point mutations affecting adsorption of phage lambda.

Gene lamB encodes the outer membrane receptor for phage lambda in Escherichia coli K12. We have determined the DNA sequence alterations of 17 lamB point mutations which result in resistance to phage lambda h+. The mutations correspond to four phenotypic classes according to the pattern of growth of three phages which use the lambda receptor: lambda h (a one-step host-range derivative of lambda h+), lambda hh* (a two-step host-range derivative of lambda h+) and K10 (another lambdoid phage). Fourteen mutations are of the missense type and correspond to Gly to Asp changes distributed as follows. One class I mutation is at position 382 of the mature lambda receptor. Seven class I* mutations, four of which at least are independent, are at position 401. Six independent class II mutations are at position 151. The three other (class III) mutations are of the nonsense type. They change codons TGG (Trp) into TAG (amber) at positions 120 (two mutations) and 351 (one mutation). Implications of these results for the topological organization of the lambda receptor as well as possible reasons for the limited number of altered sites detected are discussed.

Adsorption↗
PubMed1983

Negative dominance in gene lamB: random assembly of secreted subunits issued from different polysomes.

lamB is the structural gene for the lambda receptor, an oligomeric outer membrane protein from Escherichia coli K12 involved in phage lambda adsorption. We show that, under certain conditions, in a strain diploid for gene lamB, all the missense lamB mutations conferring lambda resistance that we have tested are dominant with respect to wild-type. We propose a model which allows a quantitative interpretation of the data. It is based on negative complementation at the level of oligomerisation. Wild-type and mutant subunits would assemble at random forming homo- and hetero-oligomers. Only wild-type homo-oligomers would be efficient for phage inactivation. For some classes of missense mutations the hetero-oligomers would have the capacity to bind, but not to inactivate the phage. The model confirms that active lambda receptor is a trimer and implies that for this secreted protein there is no preferential assembly of subunits originating from the same polysome.

Bacterial Outer Membrane Proteins↗
PubMed1983

67Ga and 59Fe uptake by tumor cells treated with hyperthermia or hyperthermia plus lanthanum.

The uptake of 67Ga-citrate and 59Fe-citrate by tumor cells treated with hyperthermia or with hyperthermia plus lanthanum has been studied. The comparison of these results with ion flux determinations (42K) appears to indicate that hyperthermia alone or combined with lanthanum modifies the ionic permeability of the plasma membrane. This phenomenon seems to be responsible for the increased accumulation of 67Ga and 59Fe.

Animals↗
PubMed1983

On the mechanisms of 67Ga and 59Fe uptake by tumors.

The uptake of 67Ga-citrate and 59Fe-citrate in the presence or absence of gallium and iron carriers, was studied on DS-sarcoma-bearing rats. Differences of uptake pattern were observed with both radionuclides. The tumor uptake of 67Ga is greatly affected by both carriers while 59Fe uptake is independent of the presence of carriers. The role of isotopic dilution, ionic competition, and the probable presence of high and low affinity binding sites in this phenomenon are discussed.

Animals↗
PubMed1983

Enhancement of hyperthermia lethality by Lanthanum.

The authors have studied the effects of La3+ during hyperthermia on tumor cells, Trypan blue exclusion and 86Rb release from previously labeled Ehrlich and DS carcinosarcoma ascites cells, indicate an increase of plasma membrane permeability by La3+ as a function of the hyperthermic level. The enhancement of hyperthermia lethality by concentration of Lanthanum over 0.5 mM after 2 hours at 44 degrees C has been demonstrated on HeLa S3 cells using a well known cloning technique. In vivo experiments have been performed on Rhabdomyosarcoma C3H bearing mice using an ultrasound heating technique at 44-46 degrees C. The preliminary in vivo results show a remarkable tumor growth inhibition and a significant increase of the survival time after only one hyperthermia treatment of 30 minutes combined with one intratumoral injection of 1 mM lanthanum. The control animal groups treated by hyperthermia alone or by lanthanum alone don't show any differences of the tumor volume evolution in comparison with untreated animal groups.

Animals↗
PubMed1982

Mutations in gene lamB: studies on structure and topology of an E. coli outer membrane protein.

Results obtained in E. coli with a set of mutations conferring tight resistance to phage lambda lead to a first identification of three residues in the lamB protein which are important for adsorption of phage lambda. Residues 151 and 382 are important for reversible adsorption while residue 401 is important for irreversible adsorption. The identification of such residues may help to identify portions of the protein located at the cell surface. Assays of lambda receptor activity in merodiploid strains heterogenote for gene lamB show that the mutations studied can have a negative dominant effect. For one class of mutations (class II) this can be interpreted by negative complementation at the level of oligomerisation. The data confirm then that active lambda receptor is a trimer.

Amino Acid Sequence↗
PubMed1982

A system for genetic analysis in gene lamB: first results with lambda-resistant tight mutants.

We describe a system for genetic analysis in gene lamb. It consists of a phage which allows mapping, complementation and sequencing studies of lamB mutations and of the sequence of gene lamB. We present results obtained with this system for a set of mutations conferring tight resistant to phage lambda. This leads to a first identification of three residues in the LamB protein which are important for adsorption of phage lambda h+. Residues 151 and 382 are important for reversible adsorption while residues 401 is important for irreversible adsorption. We briefly review other tight mutations affecting gene lamB and discuss some implications of the results on phage receptor interactions, LamB-protein structure and membrane insertion.

Adsorption↗