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G Beaubien

Publications and source records attributed to G Beaubien.

8 recordsLinked to original sources
PubMed1995

The distinct gene expression of the pro-hormone convertases in the rat heart suggests potential substrates.

The present study examined the distribution of the pro-hormone convertases PC1, PC2, furin, PACE4 and PC5 in the rat heart. Northern blot analysis of RNA extracted from cardiac tissues showed high levels of furin and PACE4 mRNA in the atria and ventricles, while PC5 mRNA was found to be expressed at high levels in the dorsal aorta. Although undetectable by Northern blot analysis, both PC1 and PC2 mRNA were detected by in situ hybridization and immunohistochemistry in discrete regions of the intracardiac para-aortic ganglia. In situ hybridization studies also showed that furin mRNA was observed in all cardiac tissues and cells, consistent with the previously reported ubiquitous expression of this gene. PACE4 mRNA was highly abundant in both the atria and ventricular cardiomyocytes, with low to undetectable levels observed in blood vessels. Finally, PC5 transcripts were expressed in the endothelial cells lining coronary vessels and the valve leaflets of the heart. The present localization studies in the heart and cardiac blood vessels suggests potential roles for each convertase in the processing of various neuropeptides, hormones and growth factors.

Amino Acid Sequence↗
PubMed1991

Gene structure and chromosomal localization of plasma kallikrein.

Plasma kallikrein (Fletcher factor) is a hepatic serine proteinase that participated in the early phase of blood coagulation. From two genomic libraries, we succeeded to isolate four overlapping clones representing the entire rat plasma kallikrein gene. Using selective DNA sequencing, polymerase chain reactions, and restriction mapping, we demonstrated that the gene for rat plasma kallikrein was 22 kb in length. Similar to human factor XI [Asakai et al. (1987) Biochemistry 26, 7221-7228], we also found that the plasma kallikrein gene is composed of 15 exons and 14 introns. A potential transcription initiation step was determined by a novel application of the polymerase chain reaction technique. Computer analysis of the 5'-promoter region of this gene revealed some putative control elements that might regulate the rat plasma kallikrein gene expression. These data and the results of chromosomal localization reported in the present study for mouse (chromosome 8) and human (chromosome 4) plasma kallikrein genes strongly corroborate a genic duplication event from a common ancestor to both plasma kallikren and factor XI.

Amino Acid Sequence↗
PubMed1991

Cloning and primary sequence of a mouse candidate prohormone convertase PC1 homologous to PC2, Furin, and Kex2: distinct chromosomal localization and messenger RNA distribution in brain and pituitary compared to PC2.

Using a 796-basepair cDNA fragment obtained from a mouse pituitary library we have screened two mouse insulinoma libraries and isolated a full-length cDNA clone (2516 basepairs; 753 amino acids), designated mPC1. The cDNA sequence of mPC1 codes for a protein containing 753 amino acids and three potential N-glycosylation sites. This cDNA encodes a putative novel subtilisin-like proteinase, exhibiting within its presumed catalytic domain 64%, 55%, and 47% amino acid sequence identity to the recently characterized candidate prohormone convertases human Furin, mouse PC2, and yeast Kex2 gene products, respectively. An identical sequence to mPC1 was derived from a cDNA library of mouse corticotroph AtT-20 tumor cells. An ArgGlyAsp tripeptide identical to the recognition sequence of integrins was observed in the structures of the mammalian PC1, PC2, and Furin. In situ hybridization results demonstrated a distinct localization of the mPC1 and mPC2 transcripts in pituitary and brain. Thus, whereas both mPC1 and mPC2 are found in the intermediate lobe of the pituitary, only mPC1 is easily detected in the anterior lobe. In extrahypothalamic regions of the brain, including cortex, hippocampus, thalamus, and spinal cord, mPC2 transcripts predominate over mPC1. Both mRNAs are found in only a fraction of hypothalamic neurons, with greater abundance of mPC1 over mPC2 in the supraoptic nucleus. The genes coding for mPC1 and mPC2 map to the murine chromosomes 13 (band 13c) and 2 (2F3-2H2 region), respectively.

Amino Acid Sequence↗
PubMed1990

Mouse plasma kallikrein: cDNA structure, enzyme characterization, and comparison of protein and mRNA levels among species.

There is differential regulation of liver mRNA levels of rat (r) and mouse (m) plasma kallikrein (PK), as observed on Northern blots. Affinity purification of mPK and rPK, microsequencing, and radioimmunoassay in either rat or mouse showed that the difference in mRNA levels does not appreciably affect the circulating PK concentration. Nuclear run-off assays demonstrated that the regulation of the mRNA level of PK is post-transcriptionally controlled. Complete cDNA sequence determination of mPK was achieved using a combination of polymerase chain reaction and lambda gt11 library screening procedures. Within the coding region, the overall sequence homology between mPK and rPK is about 91-92% in amino acid and nucleotide sequence. Although the 3' noncoding segment of mPK is shorter than that of rPK, we calculate a 53% homology with a 5% higher A/T content for mPK. The largest difference is found at the 5' end of the mRNAs: whereas rPK is predicted from its gene structure to have a 167-nucleotide leader sequence, mPK is expected to have more than 605 nucleotides, of which the last 291 are very similar to those found in the rPK gene. The regulation of the mRNA stability and/or turnover rate of PK may possibly be affected by its 5' end in a species-dependent manner.

Amino Acid Sequence↗
PubMedDate not supplied

Patient-controlled epidural analgesia with fentanyl-bupivacaine: influence of prior dural puncture.

BACKGROUND AND OBJECTIVES: Combined spinal epidural anesthesia (CSEA) involves the epidural administration of local anesthetic and opioid solutions adjacent to the prior dural puncture, potentially increasing their diffusion into the subarachnoid space. This study was designed to evaluate the influence of dural puncture on the adequacy and extent of analgesia, and drugs requirements of patient-controlled epidural analgesia (PCEA) in the postoperative period. METHODS: In this prospective double-blind study, 40 patients undergoing major abdominal surgery under general anesthesia followed with PCEA were randomly assigned to either group I (preoperative insertion of an epidural catheter) or group II (preoperative dural puncture with a 25-g Quincke needle + insertion of an epidural catheter). Postoperatively, a PCEA pump delivered an infusion of 0.1% bupivacaine + fentanyl (3 microg/mL) at 5 mL/h. Participants were allowed to self-administer 5-mL boluses of the same solution with a 15-minute lock-out interval. Hourly epidural solution requirements were recorded for 40 hours. Sensory and motor block, and pain scores were also analyzed. RESULTS: There was no difference between groups with regard to epidural solution requirements, pain scores, spread of sensory blockade, or intensity of motor block. CONCLUSION: Dural puncture with a 25-gauge Quincke needle, performed as part of CSEA, does not influence the drug requirements when a combination of 0.1% bupivacaine and fentanyl (3 microg/mL) is used for PCEA after major abdominal surgery.

Abdomen↗
PubMedDate not supplied

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DNA Mutational Analysis↗