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Biomedical subjects

M Cartier

Publications and source records attributed to M Cartier.

At least 19 recordsLinked to original sources
PubMed2000

Functional studies of a chimeric protein containing portions of the Na(+)/glucose and Na(+)/myo-inositol cotransporters.

We obtained cDNA chimeras between Na/glucose cotransporter (SGLT1) and the homologous Na(+)/myo-inositol cotransporter (SMIT) by creating random chimeras in plasmids. Of 12 chimeras, two were functional when expressed in Xenopus laevis oocytes but, upon sequencing, only one of them (C1) produced an actual chimeric protein. In C1, the first 69 amino acids of SGLT1 were replaced by the corresponding 50 amino acids of SMIT. C1 transports the same sugars as does SGLT1. C1's affinity for all sugar substrates was systematically increased by a factor of 3.3+/-0.4 but the V(max) was diminished by a factor of 15-40. In contrast, the cotransport affinity for Na(+) was unchanged. The surface expression of C1 was one seventh that of SGLT1, which explains part of the reduced V(max) and implies a significant reduction in turnover rate. N-terminal truncated constructs of SGLT1 cDNA showed that deleting amino acids 2-14 does not affect cotransporter activity, but that the pentapeptide T(14)RPVET(19) is important for normal levels of SGLT1 current. The main result of a kinetic analysis of the systematic increase in apparent affinity for sugars, together with the intact Na apparent affinity, suggests enhanced access to the sugar binding site in C1.

3-O-Methylglucose↗
PubMed1998

FCP1, the RAP74-interacting subunit of a human protein phosphatase that dephosphorylates the carboxyl-terminal domain of RNA polymerase IIO.

TFIIF (RAP30/74) is a general initiation factor that also increases the rate of elongation by RNA polymerase II. A two-hybrid screen for RAP74-interacting proteins produced cDNAs encoding FCP1a, a novel, ubiquitously expressed human protein that interacts with the carboxyl-terminal evolutionarily conserved domain of RAP74. Related cDNAs encoding FCP1b lack a carboxyl-terminal RAP74-binding domain of FCP1a. FCP1 is an essential subunit of a RAP74-stimulated phosphatase that processively dephosphorylates the carboxyl-terminal domain of the largest RNA polymerase II subunit. FCP1 is also a stoichiometric component of a human RNA polymerase II holoenzyme complex.

Amino Acid Sequence↗
PubMed1997

An essential component of a C-terminal domain phosphatase that interacts with transcription factor IIF in Saccharomyces cerevisiae.

One of the essential components of a phosphatase that specifically dephosphorylates the Saccharomyces cerevisiae RNA polymerase II (RPII) large subunit C-terminal domain (CTD) is a novel polypeptide encoded by an essential gene termed FCP1. The Fcp1 protein is localized to the nucleus, and it binds the largest subunit of the yeast general transcription factor IIF (Tfg1). In vitro, transcription factor IIF stimulates phosphatase activity in the presence of Fcp1 and a second complementing fraction. Two distinct regions of Fcp1 are capable of binding to Tfg1, but the C-terminal Tfg1 binding domain is dispensable for activity in vivo and in vitro. Sequence comparison reveals that residues 173-357 of Fcp1 correspond to an amino acid motif present in proteins of unknown function predicted in many organisms.

Amino Acid Sequence↗
PubMed1996

Accelerated stability studies of heparin.

The objective of this study was to extend our understanding of the stability of heparin. Sodium heparin, derived from porcine intestinal mucosa, was first incubated in 0.1 N hydrochloric acid and 0.1 N sodium hydroxide at 30 and 60 degrees C and sampled at times ranging from 0 to 1000 h. The absorbance spectra of the products formed under basic conditions showed an ultraviolet maxima at 232 nm associated with chemically catalyzed beta-elimination at the uronic acid residues. The products formed under acidic conditions showed a decreased staining intensity consistent with desulfation and a decrease in molecular weight corresponding to hydrolysis of glycosidic linkages when analyzed by gradient polyacrylamide gel electrophoresis. Heparin samples were next prepared in 10 mM sodium phosphate buffer at pH 7.0 in sealed ampules that had been flushed with nitrogen and incubated at 100 degrees C. Samples taken at times ranging from 0 to 4000 h were then analyzed. Heparin was relatively stable over the first 500 h, after which it rapidly degraded. Heparin, assayed using both anti-factor Xa and anti-factor IIa amidolytic methods retained 80-90% of its activity over the first 500 h, but these activities dropped precipitously, to approximately 6% and approximately 0.5% of the initial activity at 1000 h and 2000 h, respectively. This rapid decomposition began only after the buffering capacity of the solution was overwhelmed by acidic degradants, which caused the pH to decrease. Decomposition processes observed under these conditions included the endolytic hydrolysis of glycosidic linkages and loss of sulfation, particularly N-sulfate groups, and were similar to the degradation processes observed in 0.1 N hydrochloric acid. This study provides initial observations on heparin degradation pathways. More complete, quantitative studies and studies leading to the isolation and characterization of specific degradants are still required.

Animals↗
PubMed1996

[Population registration and censuses. The Chinese tradition].

"The case of China is in many ways exemplary, due to both its extremely long history and the fact that the Chinese approach influenced other countries over the course of the centuries, and can thus be viewed as a model. The first ¿censuses' were intended as an administrative tool, to manage lists of those subject to the corvee. As administrative regulations evolved, these lists were made obsolete and replaced, with the change of dynasty in 1644, by fiscal records. From 1740 to 1780, in order to link economic knowledge--especially grain prices--to the demographic situation, the central government urged local authorities to produce nominative records. Genealogies, rich in information, were another source of knowledge. With certain alterations, the Chinese model spread into the surrounding region, including Japan, Vietnam and Korea." (SUMMARY IN ENG AND SPA)

Asia↗
PubMed1995

[Family and population in China from the sixteenth to the eighteenth century in the light of a recent work by Liu Ts'ui-Jung].

Taking as its starting point the huge sample of 260,000 people born in China between the 13th and the 19th century used by Liu Ts'ui-Jung in her recent study on Lineage population, our study aims at assessing the premodern demographic evolution of China. Inasmuch the method of family reconstruction actually limited the scope of her book, Liu Ts'ui-Jung was not able to go beyond the description of a specific demographic regime defined by three elements: 1) universal marriage; 2) a moderate level of masculine fertility; and 3) a life expectation at 15 comprised between 30 and 40. These conditions would not allow the constitution of many extended households, whereas the annual rate of growth would be somewhere around 1%, a situation having little in common with the present day "population explosion". Using data included in the book, but not considered for the demonstration, we have been able to establish a dramatic deterioration of the mortality pattern from the middle of the 18th century onwards. Accordingly, the proportion of widows increases whereas population which would be characterized with a long period of growth followed by a crisis generated by a surge of the mortality rate.

China↗
PubMed1992

A frameshift mutation in the gamma E-crystallin gene of the Elo mouse.

The murine Elo (eye lens obsolescence) mutation confers a dominant phenotype characterized by malformation of the eye lens. The mutation maps to chromosome 1, in close proximity to the gamma E-crystallin gene which is the 3'-most member of the gamma-crystallin gene cluster. We have analysed the sequence of this gene from the Elo mouse and identified a single nucleotide deletion which destroys the fourth and last "Greek key" motif of the protein. This mutation is tightly associated with the phenotype, as no recombination was detected in 274 meioses. In addition, the mutant mRNA is present in the affected lens, providing further support for our hypothesis that the deletion is responsible for the dominant Elo phenotype.

Animals↗
PubMed1990

Stable, high-level expression of a carcinoembryonic antigen-encoding cDNA after transfection and amplification with the dominant and selectable asparagine synthetase marker.

The introduction and expression of cloned genes in a wide variety of animal cells requires the convenient use of dominant selectable markers. Very few of these markers can be amplified in copy number, a necessary feature if variable and high-level expression of the gene of interest is required. We describe the successful dominant transfection and amplification of a vector containing the Escherichia coli asparagine synthetase (AS)-encoding gene, asnA, transfected into a variety of human and rodent cell lines. An unlinked co-transfected expression vector containing the CEA cDNA, encoding human carcinoembryonic antigen, can be co-amplified with the asnA marker leading to extremely high levels of CEA synthesis. In addition, we show that the expression of both the asnA marker and the co-transfected CEA construct are stable in normal and amplified transfectants after prolonged culture in the absence of selective pressure.

Animals↗
PubMed1987

Use of the Escherichia coli gene for asparagine synthetase as a selective marker in a shuttle vector capable of dominant transfection and amplification in animal cells.

A new dominant amplifiable selective system for use in bacterium-animal cell shuttle vectors was developed by the insertion of a 2-kilobase genomic fragment containing the cloned Escherichia coli gene for asparagine synthetase (AS) into the pBR322-simian virus 40 recombinant vector pSV2 so as to place the translational initiator codon for the bacterial AS about 1,000 base pairs downstream from the simian virus 40 early promoter. This new construct, pSV2-AS, retains bacterial sequences for transcriptional and translational initiation and so can express AS in bacteria. The construct can also complement AS- mutants of mammalian cells, giving AS+ transfectants capable of growth in medium lacking asparagine, with relatively high efficiency (about 300 colonies per microgram of DNA per 10(6) cells exposed). The vector can be amplified up to 100-fold in such AS+ transfectants by selection in asparagine-free medium containing increasing concentrations of the AS inhibitor beta-aspartyl hydroxamate. AS+ transfectants were found to be much more resistant to a second AS inhibitor, Albizziin, than were normal AS+ animal cell lines. This difference, which may indicate a strong resistance of the bacterial AS enzyme to Albizziin, was exploited to develop an effective selection for bacterial AS transfectants of a number of wild-type AS+ cell lines of rat, Chinese hamster, mouse, and human origin. LR-73 cells, a Chinese hamster AS+ cell line, were transfected with pSV2-AS with an efficiency of about 1,000 colonies per 0.5 microgram of DNA per 10(6) cells. The integrated construct in these cells was amplified by incubation of the transfectants in increasing concentrations of beta-aspartyl hydroxamate. Advantages and disadvantages of this new dominant, selectable, and amplifiable marker over markers commonly used in shuttle vectors are discussed.

Amino Acids, Diamino↗
PubMed1986

Changes in intracardiac blood flow velocities and right and left ventricular stroke volumes with gestational age in the normal human fetus: a prospective Doppler echocardiographic study.

We used Doppler echocardiography to quantitate the changes in intracardiac blood flow velocities and right and left ventricular stroke volumes in 80 normal human fetuses from 19 to 40 weeks gestation. Blood flow velocity spectra across the aortic, pulmonary, tricuspid, and mitral valves were digitized to obtain peak velocities (m/sec) and flow velocity integrals. Aortic and pulmonary diameters were measured at valve level from two-dimensional echocardiographic images and cross-sectional area was calculated assuming a circular orifice. Ventricular stroke volume was calculated as the product of the cross-sectional area of a great vessel and the flow velocity integral through that vessel. The pulmonary arterial and aortic diameters increased linearly with gestational age (r = .82, r = .84), and pulmonary arterial diameter consistently exceeded aortic diameter. There was a positive relationship between stroke volume and gestational age: stroke volume increased exponentially from 0.7 ml at 20 weeks to 7.6 ml at 40 weeks for the right ventricle (r = .87) and from 0.7 ml at 20 weeks to 5.2 ml at 40 weeks for the left ventricle (r = .91). Similar results were obtained for right and left ventricular and combined cardiac outputs. In 44% of the fetuses it was possible to quantitate both right and left ventricular stroke volumes. There was a close correlation between right and left ventricular stroke volumes in these fetuses (r = .96) and right ventricular stroke volume exceeded left ventricular stroke volume by 28%.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1980

Nosiheptide, a sulfur-containing peptide antibiotic isolated from Streptomyces actuosus 40037.

Nosiheptide (9671 R.P.) isolated from Streptomyces actuosus 40037 (NRRL 2954) is a sulfur-containing polypeptidic antibiotic, quite different from all the other members of this family. Very active in vitro against gram-positive bacteria, it is inactive in vivo in experimentally infected mice. Not toxic, even at high dose, it may be used as a feed additive for chickens and pigs and it shows a favourable effect on the growth and conversion index.

Animal Feed↗
PubMed1980

[Not Available].

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China↗