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Biomedical subjects

P Cormier

Publications and source records attributed to P Cormier.

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

Expression of elongation factor 1 alpha (EF-1 alpha) and 1 beta gamma (EF-1 beta gamma) are uncoupled in early Xenopus embryos.

In the amphibian Xenopus laevis, the elongation factor 1 alpha proteins (EF-1 alpha) synthesised in oocytes and somatic cells correspond to distinct gene products. Furthermore, the somatic EF-1 alpha gene (EF-1 alpha S) produces one of the most highly expressed early zygotic transcripts in the embryo. The functional recycling of EF-1 alpha (conversion of EF-1 alpha-GDP to EF-1 alpha-GTP) is assured by the EF-1 beta gamma complex. We show here that in Xenopus laevis embryos, contrary to the situation for EF-1 alpha, EF-1 beta, and EF-1 gamma mRNAs are transcribed from the same genes in oocytes and somatic cells. In addition, the onset of transcription of the EF-1 beta and EF-1 gamma genes from the zygotic genome occurs several hours after that of the somatic EF-1 alpha S gene. Therefore, during early Xenopus development the expression of these three elongation factors is not co-ordinated at the transcriptional level. The consequences of this uncoupling on the efficiency of translational elongation in the early Xenopus embryo are discussed.

Animals↗
PubMed1993

Infected infrarenal aortic aneurysms: when is in situ reconstruction safe?

Twenty-five infected infrarenal aortic aneurysms operated on between 1968 and 1989 were reviewed. They were classified into post-embolic (mycotic) aneurysms (group I), infective aortitis (group II), and infected atherosclerotic aneurysms (group III). Aortoduodenal fistulas were found in eight patients and aortocaval in two. Five patients were operated on in a state of shock, and 12 had preoperative positive blood cultures. Surgical procedures included in situ reconstruction of the aorta (n = 21) and extra-anatomic bypass associated with aneurysmal resection (n = 4). In 19 patients, prostheses were covered with omental flaps, and antibiotics were continued for more than 6 weeks in all patients. In patients who underwent in situ reconstruction, three deaths were related to the initial surgery. All surviving patients were regularly followed up, and none showed any sign of late septic recurrence. In patients who underwent extra-anatomic bypass, two died in the postoperative period, one underwent reoperation 2 years after the initial surgery, and the last patient is doing well. Positive postoperative blood cultures (n = 4) revealed persistent sepsis: two cholecystitis, one spondylitis, and one aortic infection. An exhaustive review of the literature was performed; clinical, bacteriologic, and operative features and results were analyzed; prognostic factors were evaluated; and a practical therapeutic approach was suggested. The importance of preoperative diagnosis, complete resection, debridement of infected tissues, omental flap coverage, and long-term antibiotic therapy with regular computerized tomographic scanning follow-up is stressed.

Adult↗
PubMed1993

An appraisal of the developmental importance of polyamine changes in early Xenopus embryos.

The biological importance of the various changes in polyamine metabolism that occur during early Xenopus development have been investigated. Incubation of embryos in high salt medium was observed to cause a precocious fall in ornithine decarboxylase activity without affecting development. Similarly, inhibiting ornithine decarboxylase activity with specific inhibitors did not affect development. Injecting spermidine, within physiologically relevant limits, caused a dose-dependent inhibition of mitotic divisions in the injected blastomere. Increasing the intracellular putrescine did not affect cell division or development. Co-injection of both spermidine and putrescine, so that the original molar ratio of these two polyamines was conserved, abrogated the inhibition of cell division observed when spermidine was injected alone. Therefore, in Xenopus embryos the intracellular spermidine concentration must be retained within certain limits relative to that of putrescine to allow normal development.

Animals↗
PubMed1992

The right-hemisphere bias in conditional reasoning: a short report on multiple failures to replicate previous findings.

The present set of studies attempted to replicate Gellatly's (1985) findings that were supportive of Evan's (1982) hypothesis that the right hemisphere produces a selective bias towards the incorrect solution of a complex reasoning task. Subjects solved problems of the form "if p then q." In four studies, participants simultaneously performed a bottle--balancing task on each hand to interfere with processing of the reasoning task in the right hemisphere. In the fifth study, the bottle--balancing task was replaced by a finger--sequencing task. The results of the five studies did not show that the interference with right-hemisphere activity resulted in better performance on the conditional-reasoning task. It is concluded that the hypothesis of a right-hemisphere bias in conditional reasoning is still in need of reliable findings.

Attention↗
PubMed1992

Phosphorylation of Xenopus elongation factor-1 gamma by cdc2 protein kinase: identification of the phosphorylation site.

The cdc2 protein kinase phosphorylates elongation factor-1 gamma (EF-1 gamma) during meiotic maturation of Xenopus oocytes. A synthetic peptide P2: PKKETPKKEKPA matching the cDNA-deduced sequence of EF-1 gamma was an in vitro substrate for cdc2 protein kinase and inhibited phosphorylation of EF-1 gamma. Tryptic hydrolysis of EF-1 gamma and the P2 peptide, both phosphorylated by cdc2 protein kinase, resulted in multiple partial digestion products generated by the presence of barely hydrolysable bonds. The two peptides obtained from the hydrolysis of EF-1 gamma comigrated exactly in two-dimensional separation with two of the P2 peptide hydrolysates. EF-1 gamma therefore contains one unique phosphoacceptor for cdc2 protein kinase, identified as threonine-230.

Amino Acid Sequence↗
PubMed1991

Protein phosphatase 2A from Xenopus oocytes. Characterization during meiotic cell division.

A polyclonal antibody was raised against bacterially produced catalytic alpha subunit of protein phosphatase 2A (PP2AC) cloned from Xenopus ovarian library. The amount of PP2AC in Xenopus oocytes determined by Western blot analysis was 1 ng/microgram of cytosolic protein. The antibody depleted PP2AC from oocyte extracts in association with 6 components (40, 62, 65, 80, 85 and 90 kDa). Prophase- and metaphase-arrested oocytes contained identical amounts of PP2AC. Metaphase oocytes showed one specific change in the 62 kDa protein associated with PP2AC.

Amino Acid Sequence↗
PubMed1991

Analysis of risk factors for surgical wound infections following vascular surgery.

Although surgical wound infections (SWI) following implantation of prosthetic devices can be catastrophic and often require removal of the prosthesis, few studies have identified risk factors for these infections. We conducted a prospective multicenter study to identify risk factors for SWI. Of 561 vascular surgery patients enrolled in the study, 23 (4.1%) developed SWI. Multivariate analysis using logistic regression analyses identified surgery on lower extremities, delayed surgery, diabetes mellitus, past history of vascular surgery, and short antimicrobial prophylaxis (three doses of cefamandole) as independent risk factors for SWI. Consequences of SWI were serious; two (9%) died, 11 (48%) required reoperation, and five (22%) had their prosthesis removed. A risk index was developed using the independent risk factors for SWI identified by logistic regression analyses. When no risk factors were present, no SWI was observed (0 of 100), and the rate of SWI increased from 2.5% when one risk factor was present to 53.8% (7 of 13) when greater than or equal to 4 risk factors were present.

Cefamandole↗
PubMed1991

Instruction effects on gender differences in visual field advantages during lexical decision tasks.

Two experiments explored the effects of speed, accuracy, on speed and accuracy instructions on visual field advantages to lexical decisions in males and females. In Experiment 1, right visual field advantages in reaction time appeared in the groups of males in the accuracy condition and in the speed and accuracy condition. In Experiment 2, feedback consistent with the instructions was given to subjects. Females and males in the accuracy condition showed a right visual field advantage in the second block of trials. These findings suggest that cognitive variables mediate right visual field advantages to lexical decisions in males and females.

Adult↗
PubMed1991

Contribution of perceptual and lexical-semantic errors to the naming impairments in Alzheimer's disease.

The contribution of perceptual and semantic processing deficits to naming-test performance by Alzheimer's Disease subjects was examined. Groups of 34 Alzheimer subjects and 25 elderly controls completed tests of naming standard line drawings and naming perceptually degraded figures, and a test of verbal fluency for a specific semantic category. Alzheimer subjects were impaired on all measures and, when their naming-test errors were analyzed, they showed higher proportions of perceptual errors and failures to respond. Further, considerable variability in the proportions of different types of error was found both among subjects and among test items. These findings indicate that poor naming-test performance cannot necessarily be attributed to a specific deficit in semantic processing. Also, the discrepancies between previous reports of the naming deficits in Alzheimer's Disease may reflect differences in task difficulty and item selection that were apparent in this study.

Aged↗
PubMed1990

M-phase-specific cdc2 protein kinase phosphorylates the beta subunit of casein kinase II and increases casein kinase II activity.

The M-phase-specific cdc2 (cell division control) protein kinase (a component of the M-phase-promoting factor) was found to activate casein kinase II in vitro. The increase in casein kinase II activity ranged over 1.5-5-fold. Increase in activity was prevented if ATP was replaced during the activation reaction by a non-hydrolysable analogue. Alkaline phosphatase treatment of the activated enzyme decreased the activity to the basal level. The beta subunit of casein kinase II was phosphorylated by cdc2 protein kinase at site(s) different from the autophosphorylation sites of the enzyme. Phosphoamino acid analysis showed that the beta subunit was phosphorylated by cdc2 protein kinase at threonine residues while autophosphorylation involved serine residues. Casein kinase II may be part of the cascade which leads to increased phosphorylation of many proteins at M-phase and therefore be involved in the pleiotropic effects of M-phase-promoting factor.

Adenosine Triphosphate↗
PubMed1990

In vivo progesterone regulation of protein phosphatase activity in Xenopus oocytes.

Exogenous beta casein, previously phosphorylated in vitro by protein kinase A and casein kinase II, was microinjected into Xenopus oocytes to monitor in vivo protein phosphatase activities. Phosphatase activities were 1.6 and 3.4 fmol/min/oocyte, respectively, for beta casein phosphorylated by casein kinase II and beta casein phosphorylated by protein kinase A. Progesterone induced an early decrease (35% after 10 min) in phosphatase activity restricted to the protein kinase A sites of beta casein.

Animals↗
PubMed1990

Protein phosphorylation during meiotic maturation of Xenopus oocytes: cdc2 protein kinase targets.

M-Phase specific protein kinase or cdc2 protein kinase is a component of MPF (M-Phase promoting factor). During meiotic maturation of Xenopus oocytes, cdc2 protein kinase is activated in correlation with MPF activity. A protein phosphorylation cascade takes place involving several protein kinases, among which casein kinase II, and different changes associated with meiosis occur such as germinal vesicle breakdown, chromosome condensation, cytoskeletal reorganization and increase in protein synthesis. Our results provide a biochemical link between cdc2 protein kinase and protein synthesis since they show that the kinase phosphorylates in vitro a p47 protein identified as elongation factor EF1 (gamma subunit) and that the in vitro site of p47 corresponds to the site phosphorylated in vivo. Immunofluorescence showed that the elongation factor (EF1-beta gamma) is localized in the oocyte cortex. Furthermore, they show that cdc2 kinase phosphorylates and activates casein kinase II in vitro, strongly supporting the view that casein kinase II is involved in the phosphorylation cascade originated by cdc2 kinase.

Animals↗
PubMed1990

[Thrombophlebitis of the ovarian veins. A case report. Review of the literature].

The authors report on one case of thrombophlebitis of the two ovarian veins complicated by thrombosis of the vena cava inferior after a septic abortion. The diagnosis suggested by the persistence of symptoms of a severe pelvic infection was confirmed using computerized axial tomography. Faced with a clot floating in the vena cava inferior, a Greenfield filter was placed subrenally and combined with antibiotic therapy and IV heparin therapy. Clinical symptoms resolved but the scanographic image of thrombosis of the vena cava persisted after 7 months of treatment. This is a rare disease which is currently easy to diagnose, thanks to computerized axial tomography and nuclear magnetic resonance.

Abortion, Septic↗