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Biomedical subjects

M Uzan

Publications and source records attributed to M Uzan.

At least 145 records · Page 8Linked to original sources
PubMed1984

Lipid peroxides in human articular cartilage.

The hypothesis that increased generation of lipid peroxides (LP) causes articular cartilage damage in older patients and in those with osteoarthritis was tested by directly measuring LP tissue levels in various layers of human articular cartilage. The LP content was significantly greater in the superficial than in the deeper portion of the cartilage, but lower in cartilage than in liver, kidney, adrenal glands and synovium. When LP were related to the total lipid content of these tissues, a high peroxide per lipid ratio was obtained for articular cartilage. The relevance of these findings to the mechanism of cartilage fibrillation is discussed.

Adrenal Glands↗
PubMed1983

Identification and biosynthesis of the bacteriophage T4 mot regulatory protein.

The T4 mot gene regulates middle mode RNA synthesis in phage-infected cells. The mot gene product has been identified in two ways. (i) Infections with amber and temperature-sensitive mot mutants both lead to the disappearance of a number of protein bands on SDS-polyacrylamide gels. These are middle mode proteins whose synthesis depends on mot function. The mot protein disappears from such gels after infection with a mot amber mutant, but not with the mot missense mutant. (ii) This same protein is the only one to have a charge alteration when proteins from wild-type phage and mot missense mutant infections are compared by two-dimensional gel electrophoresis. Mot protein is basic and has a mol. wt. of 24 000. It migrates between the positions of gp 1 and gp IPIII on 15% SDS-polyacrylamide gels. Mot protein synthesis begins immediately after infection and continues until 4 min after infection at 30 degrees C, after which time it is strongly inhibited. This inhibition depends neither on T4 DNA synthesis nor on ADP ribosylation of the alpha subunits of the Escherichia coli RNA polymerase. The mot protein does not regulate its own biosynthesis. It is stable throughout the course of infection.

Escherichia coli↗
PubMed1982

[Anatomic incidence of meniscochondrocalcinosis of the knee].

The authors have studied the incidence of menisco-calcinosis (MC) and that of menisco-chondrocalcinosis (MCC) of knee joints of 108 non selected cadavera. The mean age of the subjects was 71.8 +/- 13.8 years. The study was performed by radiographic examination of the menisci and cartilagineous fragments of femoral condyles using high contrast films. The incidence of MC or MCC was found to be 18.5 per cent. It was slightly higher in females (21.5 p. cent) than in males (15.8 p. cent) subjects but this difference failed to reach the level of statistical significance. No positive case was detected before the age of 60 years. For the age groups of: 60-69, 70-79, 80-89 and over 90 years, its incidence was: 11.7; 26.9; 21.2 and 50 (4 subjects out of 8) per cent respectively. Approximately 40 per cent of all positive cases had meniscocalcinosis without associated chondrocalcinosis. No single case of chondrocalcinosis without meniscocalcinosis was observed. Six out of 8 cases with MC calcinosis and 2 out of 12 cases with MCC were unilateral. The external menisci were more frequently and more heavily affected than internal ones. Eighty per cent of the knees affected by either MC or MCC were at the same time associated to an osteoarthrotic lesion compared to 35 p. cent of the knees without MC or MCC matched for age: a result which appeared to be highly significant difference.

Aged↗
PubMed1981

Genetical and structural analysis of a group of lambda ilv and lambda rho transducing phages.

Eight lambda ilv C transducing phages generated from E. coli K12 secondary site lysogens have been analysed genetically and physically. Two of them carry, in addition, the rho gene and its promotor region, but not the cya gene. The ilv O 603 mutation has been located between ilv G and ilv E. Electrophoretic analysis of the proteins synthesized by these phages in a system of UV irradiated cells allowed us to assign molecular weights of 55000 and 66000 daltons to the ilv C and the ilv D gene products, respectively, and to show that an ilv G-encoded polypeptide of 60000 daltons is made from an ilv O- but not from an ilv O+ phage. The expression of the ilv G gene is discussed in the light of the recent finding of a promoter-attenuator region lying upstream to ilv G. Finally, we have found that one of the lambda ilv phages does not have the classical structure of a transducing phage.

Amino Acids, Branched-Chain↗
PubMed1978

Correlation between the serine sensitivity and the derepressibility of the ilv genes in Escherichia coli relA- mutants.

Upon addition of excess one carbon metabolites (including serine)bacteria stop growing because of isoleucine starvation. After such treatment stringent bacteria rapidly resume normal growth whereas relaxed mutants remain unable for some time to grow. We show here that this is due to a lack of derepressibility of ilv genes after the starvation period. Results are also presented which show that RNA polymerase structural mutants may be selected among the clones resistant to a mixture of serine, methionine and glycine, in relA- strains. Finally circumstancial evidence suggests that the one carbon metabolism may be involved in a process controlling isoleucine metabolism.

DNA-Directed RNA Polymerases↗
PubMedDate not supplied

Fatal sepsis due to Escherichia coli after second-trimester amniocentesis.

The case of a pregnant woman (16th week) needing an amniocentesis is reported. She rapidly developed a septic shock. Despite vaginal delivery, curettage and antibiotherapy, the patient deteriorated with the onset of an acute respiratory distress syndrome and a typical disseminated intravascular coagulation. Bacteriological data showed positive blood cultures to Escherichia coli. Amniotic liquid was positive to the same E. coli. Cultures obtained from instruments, disinfectant solutions and gel used during the procedure were negative. On the contrary, amniotic and fetal cultures were positive to E. coli and Clostridium perfringens. She died 2 days later. The incidence of septic shock following amniocentesis is very low but we report the first case of fatal sepsis and multiorgan failure, due to E. coli and C. perfringens. The mechanisms of infection are discussed: contamination from the instruments, systemic dissemination of bacteria coming from an asymptomatic intra-amniotic infection, and inoculation of the placenta with a needle passing through the bowel.

Adult↗
PubMedDate not supplied

Usefulness of fluorescence in situ hybridization for the diagnosis of Turner mosaic fetuses with small ring X chromosomes.

OBJECTIVE: To emphasize the usefulness of fluorescence in situ hybridization (FISH) techniques on uncultured amniocytes for the diagnosis of abnormal mosaic karyotypes. METHODS: In the course of three prenatal diagnoses, specific fluorescent probes, coding, respectively, for chromosomes X, Y, 18, 13, and 21, were applied on amniocyte preparations directly after amniocentesis. At least 50 nuclei were counted in each case. Parallel to the FISH procedure, cell cultures were set up in order to obtain karyotypes. FISH and cytogenetic results were then compared. RESULTS: In each case, FISH showed an abnormal mosaic chromosomal constitution, 45,X/46,XX, which was related to the existence of tiny ring X chromosomes in karyotypes. CONCLUSION: Because very small ring X chromosomes can escape identification when standard cytogenetic techniques are used alone, we show that misdiagnosis can be avoided when FISH is performed beforehand.

Adult↗
PubMedDate not supplied

Fetal-placental and decidual-placental units: role of endocrine and paracrine regulations in parturition.

In primates, fetal adrenal and placental steroidogenic enzymatic systems are complementary in a fetal-placental unit, synchronizing fetal maturation and myometrial activation in late gestation. Moreover, as hemochorial placentation characterizes rodents and primates, paracrine regulations between decidua and placenta are essential to the immunotolerance of the conceptus and its development. Thus, the decidual-placental unit remains in a striking state of decidual quiescence throughout gestation, and the reversal of this quiescence is thought to play a key role in myometrial stimulation and the onset of parturition. A comprehensive view of the control of myometrial contractility, through the interaction of paracrine and endocrine modifications in late gestation, is proposed. The failure of these mechanisms underlie prematurity and the use of fetal therapy in threatened preterm labor.

Animals↗
PubMedDate not supplied

Intervillous and spiral artery flows in normal pregnancies between 5 and 10 weeks of amenorrhea using color Doppler ultrasonography.

OBJECTIVE: The aim of our study was to investigate early placental circulation development and spiral and uterine artery flows in normal 1st-trimester pregnancies. METHODS: A prospective study of intervillous and spiral artery flows in 49 normal pregnancies (5-10 weeks of amenorrhea) was performed. Transvaginal color and pulsed-wave Doppler techniques (6-MHz probe) were used as routine ultrasound scanning modalities before pregnancy termination for psychosocial reasons. RESULTS: In all pregnancies, between 5 and 10 weeks, continuous nonpulsatile intervillous flow (mean V(max) 3.55 cm/s) and spiral artery flow (mean peak systolic velocity 16.2 cm/s, mean diastolic index D/S 0.49 +/- 0.089) were detected. In the 47 women in whom the uterine artery flow was measured, the mean peak systolic velocity was 67.5 cm/s, the mean diastolic index was 0.12, and bilateral notching was observed. CONCLUSIONS: In all cases, between 5 and 10 weeks, slow and continuous nonpulsatile intrachorionic flow could be detected, whereas pulsatile flow was detected in spiral arteries. The true nature of this early intervillous circulation remains to be determined.

Adolescent↗