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F Lasmoles

Publications and source records attributed to F Lasmoles.

36 records · Page 2Linked to original sources
PubMed1991

Parathyroid hormone related protein (PTHrP) and breast cancer.

PTHrP, a newly characterized peptide is responsible for humoral hypercalcemia of malignancy in squamous cancers. It is also expressed by a variety of normal tissue and might have growth factor propriety. It is expressed by lactating breast and is frequently present in breast cancer. Although it is responsible for humoral hypercalcemia in an animal model of breast cancer its role in breast cancer hypercalcemia is still putative. The possibility that it might be one of the autocrine growth factors implicated in breast cancer cell proliferation has been suggested.

Animals↗
PubMed1990

PCR amplification of CGRP II mRNA. Variable expression in tumoral and non-tumoral human thyroid.

Two genes code for calcitonin gene-related peptides (CGRPs). One expresses by tissue-specific alternate splicing calcitonin and CGRP I mRNAs, the other CGRP II mRNA. Calcitonin is the marker of sporadic or hereditary human medullary thyroid carcinoma (MTC). CGRP II expression is not well established in normal or tumoral thyroid. After amplification by polymerase chain reaction, CGRP I and II mRNAs were detected in six cases of MTC associated with other endocrine neoplasia (MEN IIa) and in two cases of isolated MTC. CGRP I was detected in all non-C cell tumoral thyroids (6 samples), CGRP II was barely detectable in three out of six cases. CGRP II could be a specific tumoral marker of MTC.

Base Sequence↗
PubMed1990

Predicted structure of rabbit N-terminal, calcitonin and katacalcin peptides.

Poly A rich RNA was extracted from rabbit thyroid and cDNA obtained by the action of reverse transcriptase. The cDNA was used to construct a library in lambda GT 11. Screening of the library with a radio-labelled probe specific for human calcitonin allowed the isolation of a clone containing an open reading frame with a high homology with human and murine exon 4 of calcitonin/calcitonin gene-related peptide gene. This sequence codes for a typical calcitonin precursor. We deduced the amino acid sequence of rabbit N-terminal peptide, calcitonin and katacalcin.

Amino Acid Sequence↗
PubMed1987

Sequence and expression of the chicken calcitonin gene.

The avian calcitonin gene was isolated and sequenced; two mRNAs are expressed by tissue-specific alternate splicing. The peptides encoded by the mRNAs are the protein precursors of either calcitonin or calcitonin gene-related peptide (CGRP). Calcitonin is expressed predominantly in ultimobranchial bodies and CGRP in brain.

Amino Acid Sequence↗
PubMed1986

Isolation and partial characterization of the calcitonin gene in a lower vertebrate. Predicted structure of avian calcitonin gene-related peptide.

The gene coding for calcitonin was isolated and characterized in a non-mammalian vertebrate, chicken. Sequencing of the 3'-end of this gene revealed after the calcitonin coding exon, an intron followed by an exon coding for a calcitonin gene-related peptide, which displays significant amino acid sequence homology with mammalian CGRPs so far sequenced.

Amino Acid Sequence↗
PubMed1985

Elucidation of the nucleotide sequence of chicken calcitonin mRNA: direct evidence for the expression of a lower vertebrate calcitonin-like gene in man and rat.

Calcitonin shows considerable divergence in amino acid sequence between lower vertebrates and higher vertebrates. Immunoreactive salmon-like calcitonin molecules are present in the thyroid of man and rat. Elucidation of the almost complete sequence of chicken calcitonin mRNA revealed that the calcitonin precursor in chickens had the same organisation as in higher vertebrates (man and rat) but showed considerable differences in amino acid sequence. cDNA probes specific for chicken calcitonin mRNA hybridized to poly(A)-rich RNA extracted from a case of medullary carcinoma of the thyroid and from murine thyroid. These results suggest the expression in man and rat of a gene coding for an avian calcitonin-like precursor.

Amino Acid Sequence↗
PubMed1984

Rapid increase of calcitonin-specific mRNA after acute hypercalcemia.

The regulation of calcitonin (CT) secretion by calcium was studied by measuring CT mRNA extracted from thyroids of normal rats subjected to acute calcium stimulation in vivo. The 15000-Mr primary translation product of CT mRNA was identified by immunoprecipitation using specific antibodies. While total mRNA and total radioactivity incorporated after translation of total mRNA remained unaffected by the calcium stimulation, a fourfold increase in radioactivity incorporated in CT primary translation product occurred as early as 2 min after calcium administration. This peak coincided with a rise in plasma levels of the hormone and preceded a detectable decrease in tissue stores. These results suggest that calcium ion, either directly or indirectly via its action on intracellular stores of the hormone or its precursors, causes a rapid increase in cell levels of translatable CT mRNA. In view of the extremely short time (2 min) in which this increase occurs, the action is probably at the post-transcriptional level as no increase in CT mRNA levels could be detected by hybridization assay using a specific cDNA probe for human CT mRNA.

Acute Disease↗
PubMed1984

The complete sequence of human preprocalcitonin.

DNA complementary to mRNA extracted from the thyroid glands of patients suffering from medullary carcinoma of the thyroid (MCT), a calcitonin-producing tumour, was inserted in the Pst site of pBR 322 by G-C tailing. The recombinant plasmids were used to transform Escherichia coli DP 50. Ampicillin-resistant clones were screened using a 32P-labelled cDNA to mRNA extracted from a case of MCT particularly rich in calcitonin (CT) mRNA. Positive clones were subsequently rescreened using a 32P poly(T) probe. Eighty clones were thus purified, and the inserts obtained by digestion with PstI were subjected to positive hybridization selection with subsequent translation in vitro. An insert stimulating synthesis of the protein and containing restriction sites compatible with the previously published complete sequence of calcitonin mRNA from rat was sequenced. This cDNA insert contained the entire coding region of 426 bp, 70 bp at the 5'-end, and 295 bp upstream from the poly(A) tail. The complete amino acid sequence of human preprocalcitonin could thus be deduced.

Amino Acid Sequence↗
PubMed1984

Ultimobranchial gland of the domestic fowl. Two types of secretory cells involved in calcitonin metabolism.

The ultimobranchial gland (UBG) of birds is particularly rich in calcitonin, the hypocalcaemic hypophosphataemic hormone, that is secreted by the C-cells of the mammalian thyroid. The principal cells of the UBG have a striking resemblance with the mammalian C-cells, i.e., they possess small intracytoplasmic dense-core secretory granules, 150-300 nm in diameter. The gland also contains a second, morphologically distinct, endocrine cell type with larger granules, 500-800 nm in diameter. A sensitive immunocytochemical reaction was developed with the use of antibodies against salmon calcitonin. By means of this technique the presence of calcitonin-immunoreactive molecules was demonstrated in both secretory cell types of the UB gland of the chicken. This gland can thus be considered as a homogeneous calcitonin-producing tissue. Whether the secretory products are identical is discussed and differences in the secretory pathways are suggested.

Animals↗
PubMed1983

Cell free translation of chicken calcitonin messenger RNA.

The primary step of calcitonin biosynthesis was studied in a normal organ: chicken ultimobranchial gland, a tissue particularly rich in calcitonin secretory cells. Poly(A)-rich RNA was extracted and purified from ultimobranchial organs and translated in a reticulocyte lysate in the presence of labelled methionine. Polyacrylamide gel electrophoresis of specific immunoprecipitates revealed a major band of Mr 14 500 and a band of Mr 13 300. Thus, in chicken the precursor of calcitonin is a Mr 14 500 polypeptide. The minor component of Mr 13 300 could represent limited processing by the reticulocyte lysate.

Animals↗
PubMed1980

Effects of thymic factors on growth of experimental tumors.

The effects of thymic factors on the growth of a chemically induced tumor have been studied. The thymic factors were obtained by a gentle isolation procedure which minimizes loss of material and biological activity. The administration of the thymic factors neither influenced the development or growth of the tumor nor the weight of the thymus or the spleen. A bigger thymus and a smaller spleen were observed in animals rejecting the tumor, whether or not they received the thymic factors.

Animals↗
PubMed1979

Chromatographic isolation of thymic factors impairing neuromuscular transmission.

Thymopoietins I and II are chemically related peptides able to inhibit neuromuscular transmission. They were first isolated from bovine thymus by a protein-denaturating method, which may have destroyed other thymic factors displaying the same biological activity. The present investigation, based on a new gentle isolation procedure, suggests that thymopoietins are the only factors impairing neuromuscular transmission that are present in the thymus. The yield of the new procedure is at least twice as high as that of the original method.

Animals↗
PubMed1977

Serum thymic factor and the neuromuscular transmission.

The effect of Serum Thymic Factor (FTS) on neuromuscular transmission has been studied in vivo by electromyographic assay. As no modification of muscle tetanus pattern was detected, the involvement of this factor in the pathology of thymus disorders leading to myasthenia is unlikely.

Animals↗
PubMedDate not supplied

Quantification of intracellular calcitonin gene transcripts in human medullary thyroid carcinoma (MTC) by in situ hybridization.

The human calcitonin gene generates 2 distinct mature mRNAs by alternative RNA processing, encoding calcitonin (CT) in thyroid C-cells or a neuropeptide (CGRP) in the brain. We evaluated quantitatively by in situ hybridization the expression of the CT gene in tissue section of 5 MTCs (2 sporadic and 3 familial forms). The primary tumor of one MTC was compared to a brain metastasis. In situ hybridization was carried out with tritiated cDNA probes coding for CT and CGRP mRNA. After autoradiography the number of silver grains was counted in 400 cells by computerized analysis of digitized images and expressed as the labelling level (L.L. = grain area/cell area per day of autoradiographic exposure). This was used to calculate the relative abundance per cell of the specific messengers studied, which depends on the autoradiographic efficiency and the specific activity of the probe used. The CT mRNA content was 3.25-6.55 10(-10) micrograms equivalents in the 3 familial forms of MTC and 4.95-9.25 10(-10) micrograms equivalents for the 2 sporadic forms. The levels of CT mRNA in the brain metastasis and in the primary tumor were identical (4.10 10(-10) micrograms equivalents). CGRP mRNA expression was weaker in the sporadic and in the familial thyroid tumors (0.60-1.65 10(-10) micrograms equivalents). The content of mRNA CGRP in the brain metastasis (0.60 10(-10) micrograms equivalents) was lower than that in the primary tumor (1.05 10(-10) micrograms equivalents).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Expression of CGRP mRNAs in the pink salmon, Oncorhynchus gorbuscha.

We report the isolation of calcitonin gene-related peptide (CGRP) mRNAs and expression of these RNAs in different tissues in the pink salmon, Oncorhynchus gorbuscha. Hybridization of poly(A+) RNAs indicated a mature CGRP RNA of 1.1 kb. The CGRP-like immunoreactivity occurring in tissues and plasma had the same relative molecular weight as the synthetic molecule. Variations in CGRP plasma levels were observed during migration, spawning, and postspawning states. These data suggest that CGRP may play an important role during the reproductive cycle of salmon.

Animals↗