[Multiple hematomas caused by acquired factor VIII inhibitor].
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Aged↗
Biomedical subjects
C Collet
Publications and source records attributed to C Collet.
Exon organization and sequence of the genes encoding alpha-lactalbumin and beta-lactoglobulin from the tammar wallaby (Macropodidae, Marsupialia).
Clones encompassing the genes encoding alpha-lactalbumin and beta-lactoglobulin were isolated from a tammar wallaby genomic library, the exons localized using end-labeled oligonucleotides and the DNA sequences determined. The tammar beta-lactoglobulin gene has the same 7 exon-6 intron structure as the sheep homologue. Potential binding sites for mammary gland-specific transcription factors were identified, on the basis of similarity to sites in the sheep gene, in the promoter region of the tammar beta-lactoglobulin gene. The tammar gene encoding alpha-lactalbumin appears to contain four introns rather than three as are present in the eutherian homologues, or the evolutionarily related lysozyme gene. The additional intron appears to occur within the 5' noncoding region of the tammar gene.
Amino Acid Sequence↗
Bioelectric and microcirculation cutaneous sensors for the study of vigilance and emotional response during tasks and tests.
Bioelectronic phenomena related to the activity of the Autonomic Nervous System (ANS) activity mainly take place in the deep part of the brain where they are difficult to record. The hand skin, being richly innervated by sympathetic efferent fibres, offers an interface from which relevant ANS-related signals can be recorded. Two non-invasive bioelectronic measurements (skin resistance and potential) reflecting the activity of the ANS were performed at the skin surface. These measurements were complemented by thermovascular (skin microcirculation and skin temperature) and cardiorespiratory (instantaneous heart rate and instantaneous respiratory frequency) measurements. The bioelectric measurements were performed using noninvasive Ag/AgCl electrodes. Non-metallic NASICON (Na Super Ionic Conductor) electrodes were tested and compared with traditional electrodes for the optimization of bioelectric measurements. Signal analysis and data processing was accomplished by means of original indices on a specially designed PC-based software. The methodology was used to evaluate vigilance level, mental workload, and emotional response during tasks (sporting activity, mental calculation, olfactive stimuli) and in critical situations (car crash avoidance).
Accidents, Traffic↗
Higher female than male recombination rates in a marsupial mammal, the tammar wallaby (Macropus eugenii).
Previous work has shown that females have lower recombination rates than males in two distinctly related marsupial species, an American didelphid and an Australian dasyurid. We report here that the tammar wallaby (Macropus eugenii), which belongs to a third major group, has higher female recombination rates in two linked pairs. The nature of the sex differences in recombination rates in this species is thus similar to the situation in eutherian mammals.
Animals↗
Autonomic responses correlate to motor anticipation.
New findings have stated that autonomic nervous system (ANS) functioning may reflect some cognitive processes observed in real time analysis. Four ANS variables plus instantaneous heart rate and respiratory frequency were quantified by original techniques and indices on 11 subjects during a coincidence-anticipation task, performed on a computer screen under six different, randomly-presented modalities (3 modalities describing the spot moving along a parabola at 2 speeds). Tonic levels and phasic responses corresponding to each trial were recorded continuously. Results showed that skin resistance tonic level evolution gave evidence of vigilance changes. Thus, performance can be related to subjects' vigilance. An autonomic response was always observed during performance of an anticipation task. The six task modalities were distinguished by performance values. Simultaneously recorded ANS responses fully differentiated these same modalities for 10 subjects out of 11. These ANS responses were furthermore related to performance. Ten subjects out of 11 possess at least one Autonomic variable which can differentiate the six task modalities, confirming Lacey's hypothesis on ANS preferential response, and suggesting ANS specificity. ANS functioning may reveal some brain functions through a specific autonomic channel, characterizing each subject. The behavioral output of an individual may thus be reflected by such a functioning.
Adolescent↗
The identification of nuclear and mitochondrial genes by sequencing randomly chosen clones from a marsupial mammary gland cDNA library.
To increase the number of genes that can be mapped to the genome of the tammar wallaby (Macropus eugenii), we sequenced 100 randomly chosen clones from a mammary gland cDNA library. Provisional identifications were made of seven nuclear genes and one mitochondrial gene encoding two caseins, beta-galactosidase, acetyl-coenzyme A synthetase, lipoprotein lipase, inorganic pyrophosphatase, an ATP-dependent RNA helicase, and cytochrome c oxidase I. Highly conserved genes, such as that encoding acetyl-coenzyme A synthetase, were easily identified even from cross-kingdom matches. Genes which are highly divergent, however, such as those encoding the mature casein peptides, could not be aligned with homologues in the databases. Even in an organ where there is high mRNA species redundancy, the sequence characterization of expressed sequence tags provides a rapid means of gene identification for mapping purposes.
Amino Acid Sequence↗
Consistent variation in amino-acid substitution rate, despite uniformity of mutation rate: protein evolution in mammals is not neutral.
Variation in mutation rate, attributed to differences in both generation time and in metabolic rate, has been invoked under the neutral theory of molecular evolution to account for differences in substitution rate among mammalian lineages. We show that substitution rates at fourfold-degenerate sites and at sites in noncoding regions do not vary between the primate and rodent lineages, implying mutation-rate uniformity. In contrast, the substitution rates at nondegenerate sites vary both within and between lineages. This difference in substitution-rate pattern between the two types of site is incompatible with neutral theory but may result from substitutions occurring by fixation of slightly deleterious mutations. Variation in the rate of protein evolution among mammalian lineages appears to be due more to differences in population fixation rates than to biochemical or physiological differences affecting mutation rates.
Animals↗
Double staining in situ study of mRNAs encoding milk proteins in the mammary gland of the tammar wallaby (Macropus eugenii).
Oligonucleotides, differentially tagged with fluorochromes, were used to determine whether the distribution of mRNAs encoding the major milk proteins is heterogeneous within the mammary gland of the tammar wallaby (Macropus eugenii). This method also allowed direct visualization of two species of mRNA within the same cell. Sections of early and late lactating glands of tammar wallabies were hybridized with oligonucleotides labelled with fluorescein isothiocyanate or rhodamine isothiocyanate either alone or in combination. The results support the hypothesis that milk secretion is an all-or-none process with all epithelial cells in a given alveolus producing the same suite of milk proteins. In tammar wallabies, a gene encoding a protein specific to the latter phase of lactation appears to be expressed in those cells already secreting the other major milk proteins.
Animals↗
[Immunoassay and measurement of the biological activity of serum hLH: results obtained of a multicenter study].
The discrepancy between results obtained using different anti-hLH antibodies available on the market led us (in the context of a contract with the CNAMTS) to compare the results of hLH immunoassays (eight different reagents) with those of hLH bioassays based on the measurement of the steroidal activity of this hormone on mouse, rat or pig testicular preparations (five methodologies). Twenty-nine samples of serum or human serum pools were tested. The values resulting from these tests reveal differences linked to the nature of the antibodies or to the methodological conditions used for the testicular preparations. Some antibodies seem unable to identify some hLH forms which, however, can be detected by biological methods.
Adult↗
A novel member of the lipocalin superfamily: tammar wallaby late-lactation protein.
The finding that tammar wallaby late-lactation protein is linked to beta-lactoglobulin prompted a search of current GenPeptide and NBRF-PIR protein databases for sequence similarities to late-lactation protein. Similarities were found to von Ebner's gland protein and other members of the lipocalin superfamily of proteins. A conservative replacement of Trp with Tyr suggests that late-lactation protein may represent an unusual member of this protein superfamily.
Amino Acid Sequence↗
Hypothalamic-pituitary activation does not differ during human and porcine insulin-induced hypoglycemia in insulin-dependent diabetes mellitus.
Although pituitary hormones play only a minor role in acute hormonal counterregulation during insulin-induced hypoglycemia, their concomitant secretion with the profound sympathoadrenal response provides an indicator of hypothalamic-pituitary activation. The release of different amounts of beta-endorphin, growth hormone, and adrenocorticotropin during human (HI) and porcine (PI) insulin-induced hypoglycemia would serve as a pointer to a different insulin species effect on hypothalamic-pituitary response. We performed a controlled, double-blind study with randomization to either HI or PI to compare insulin effects during developing and established hypoglycemia. The glucose clamp technique was used to lower the blood glucose concentration stepwise (3.3, 2.2, 1.7 mmol/l) over similar periods in ten patients with insulin-dependent diabetes mellitus. beta-endorphin, growth hormone, and adrenocorticotropin levels were determined by radioimmunoassay from arterialized blood at the above plateaus. A different action of HI or PI on peripheral glucose metabolism was not found. Pituitary hormones increased significantly during hypoglycemia (analysis of variance for hypoglycemic effects: beta-endorphin, P < 0.02; growth hormone, P < 0.04; adrenocorticotropin, P < 0.05). No insulin species effect was detected. Hypothalamic-pituitary activation during insulin-induced hypoglycemia is independent of the insulin species used, which supports earlier observations of an identical sympathoadrenal response during HI- and PI-induced hypoglycemia.
Adrenocorticotropic Hormone↗
Use of a subspecies cross for efficient development of a linkage map for a marsupial mammal, the tammar wallaby (Macropus eugenii).
The tammar wallaby (Macropus eugenii) has a 2n = 16 karyotype with an XX/XY female/male sex dimorphism. Female reproduction can be manipulated to produce up to five offspring per year. We have crossed two genetically distant subspecies of tammars, one from Kangaroo Island in South Australia, the other from Garden Island in Western Australia, to produce fertile F1 offspring of both sexes. Male F1 hybrids were crossed with female Kangaroo Island tammars to produce over 80 phase-known backcross progeny for linkage studies. Here we report detection of two linkage groups derived from these male recombination values. The first consists of alpha-lactalbumin and an anonymous tammar cDNA clone, pB72; the second contains the gene for a marsupial-specific milk protein (late lactation protein), the gene for lipoprotein lipase, and an anonymous cDNA clone, pB65. The gene for late lactation protein has previously been assigned to tammar chromosome 3.
Animals↗
Molecular characterization and in-vitro hormonal requirements for expression of two casein genes from a marsupial.
Two marsupial casein genes have been isolated from a tammar wallaby (Macropus eugenii) mammary gland cDNA library. Comparisons of the tammar alpha- and beta-casein genes with their eutherian homologous reveal extensive divergence at the levels of nucleotide and amino acid sequences. Regions of similarity between the tammar and eutherian Ca(2+)-sensitive caseins are restricted to the major phosphorylation sites and the signal peptides. Quantification of casein mRNA levels in hormone-stimulated mammary gland explants from tammars in late pregnancy suggests that maximal induction of the beta-casein gene is dependent upon prolactin and insulin, while maximal induction of the alpha-casein gene is dependent upon prolactin, insulin and cortisol. These results are in contrast to earlier studies which show that the maximal induction of a putative 19 kDa casein, alpha-lactalbumin and beta-lactoglobulin in the tammar mammary gland is dependent upon prolactin alone. The expression of the latter three genes is not modulated by other hormones known to play a role in the in-vitro initiation of lactation in eutherians.
Amino Acid Sequence↗
[Food diaries in the follow-up of obese patients].
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Diet Records↗
Hormone-responsive survival of mammary gland explants from the pregnant tammar wallaby (Macropus eugenii) in the absence of exogenous hormones and growth factors.
1. The level of beta-lactoglobulin mRNA increased maximally in mammary explants from late pregnant tammars cultured for 3 days in media containing either prolactin or insulin, cortisol and prolactin. 2. The same level of accumulation occurred when explants were first cultured for 4 days in a chemically defined medium with no exogenous hormones, serum or growth factors, suggesting that the tissue remains viable and hormone-responsive during the initial incubation. 3. Mammary explants cultured for 4 days in medium with no hormones demonstrated a progressive increase in the rate of RNA and DNA synthesis suggesting that the tissue is under a positive autocrine/paracrine stimulus.
Animals↗
Chromosomal localization of the gene for late lactation protein (LLP) in the tammar wallaby (Macropus eugenii).
The gene coding for the late lactation protein (LLP) in Macropus eugenii has been mapped using in situ hybridization to the proximal region of the long arm of chromosome 3. This position was confirmed by means of exclusion Southern blot analysis.
Animals↗
A marsupial beta-lactoglobulin gene: characterization and prolactin-dependent expression.
Analysis of the tammar wallaby beta-lactoglobulin cDNA and inferred amino acid sequences reveal extensive sequence divergence from the eutherian beta-lactoglobulins. Conserved residues include the cysteines and a number of individual amino acids involved in structure and ligand-binding. The only region of extended similarity is a heptapeptide sequence which may impart specificity to its interaction with a receptor protein. Northern analysis of total mammary RNA revealed two transcripts which result from differential utilization of polyadenylation signals. The concentration of beta-lactoglobulin mRNA increased in late lactation and correlates with increases in milk production and levels of milk fat. Quantification of beta-lactoglobulin mRNA levels in hormone-stimulated mammary gland explants from tammars in late pregnancy suggests that maximal induction of the gene is dependent on prolactin alone and that expression is not modulated by other hormones known to play a role in the initiation of lactation in eutherians.
Amino Acid Sequence↗
[Allo-immune neonatal thrombopenia in the BaK(a) system. Apropos of 2 familial cases].
The authors report a case of two siblings who developed a neonatal alloimmune thrombocytopenia (NAITP) due to Bak-System incompatibility. They review the platelet antigen systems involved in NAITP and raise the problem of its present antenatal and postnatal management.
Antigens, Human Platelet↗