Biomedical subjects
S Alonso
Publications and source records attributed to S Alonso.
Assessment of the breeding prognosis of mares using paired endometrial biopsy techniques.
Paired endometrial biopsy samples were taken from 530 subfertile mares, before and after treatment (where indicated) and a period of sexual rest. Prognoses were made after each biopsy (Categories 1A-4A before treatment and Categories 1B-4B after treatment), using histopathological criteria similar to those described by Kenney and Doig (1986). Eighty-seven per cent of the mares were assigned to first biopsy prognosis Category 3A. The second biopsy prognosis produced a more even population distribution (10, 47, 40 and 3 per cent respectively for Category 1B, 2B, 3B and 4B mares). First biopsy Category 3A and 4A mares produced mean foaling rates of 51 and 40 per cent respectively. None of the 14 second biopsy Category 4B mares delivered a live foal (12 were barren, one aborted and one suffered early foetal death). This study supports the hypothesis that a breeding prognosis assigned on the basis of two endometrial biopsy samples, taken before and after specific uterine treatment, where indicated, which takes into consideration the mare's ability to respond to treatment, is likely to be more accurate than one assigned after a single biopsy sample.
The effect of age and parity on the development of equine chronic endometrial disease.
The results of a retrospective analysis of 3,804 endometrial biopsy specimens collected from non-pregnant mares during the course of routine equine stud farm practice demonstrates a significant and practically useful correlation between the severity of chronic degenerative endometrial disease (CDE) diagnosed and age of mare at the time of examination. There were significant correlations between the number of foals born and the mares' barren years prior to biopsy and the severity of CDE, but the differences were not sufficiently large to be useful. Correlations between the severity of chronic infiltrative endometritis (CIE) and age or pre-biopsy parity were minimal. The results suggest that using similar histopathological criteria to those used by Kenney and Doig (1986), mares up to nine years of age should have no signs of CDE, mares up to 13 years of age should have no more than mild signs, mares up to 15 years of age should have no more than moderate signs and mares aged 17 years or older are likely to have severe signs. We believe that these guidelines are a useful, objective aid for formulating a breeding prognosis.
Acute and chronic metabolic acidosis in the pig: renal metabolism and ammoniagenesis.
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[Research of gene(s) involved in situs inversus. Initial results].
Reverse Genetics consists in identifying the gene responsible for a hereditary condition, the biochemical mechanism of which is unknown. We have applied this approach to families recruited according to the following criteria: 1) at least two members of the family must be affected; 2) one of the two subjects must have an abnormality of thoracic and/or abdominal lateralization. This abnormality of situs can form part of a syndrome: asplesia, polysplenia, heterotaxia, dextrocardia, situs inversus, Kartagener' or Ivemark's syndrome; 3) the other affected subject(s) must have some form of congenital heart disease and/or one of the phenotypes above described in 2); 4) in consanguinous marriages, only one child fulfilling the criteria in 2) above described is required. Eight families conforming to the above criteria are presented; lymphocytic transformation was successful in 90% of cases when the blood sample was received within 48 hours. The segregation of the alleles is in favour of a linkage between the tested probe and the syndrome(s) studied. In order to identify the gene responsible, we will have to increase the number of families studied and extend our research to sporadic cases.
Genetic analysis of the interaction between cardiac and skeletal actin gene expression in striated muscle of the mouse.
The two sarcomeric actin genes, encoding alpha-cardiac and alpha-skeletal actins, are co-expressed in striated muscle, but in the adult the respective isoform predominates in cardiac or skeletal muscle of the normal mouse. We have investigated the interaction between this gene pair in different genetic contexts. Northern blot analysis of alpha-actin mRNA levels in different inbred mice (129/SJ, C3H, C57BL/6) demonstrates variation of as much as threefold in skeletal muscle and eightfold in cardiac muscle. High or low-level expression is seen for both skeletal and cardiac muscle in a given line, suggesting common regulatory phenomena affecting the abundant alpha-skeletal or alpha-cardiac transcript. In the BALB/c mouse, which has a mutant cardiac actin locus, skeletal as well as cardiac actin mRNA and protein accumulate in the adult heart. We have analysed the role of the two alpha-actin genes in this phenomenon in seven recombinant inbred mouse lines (BALB/c x C57BL/6) and in a cross (BALB/c x C3H). The results demonstrate that neither alpha-actin gene alone is sufficient, and implicate other regulatory loci. DNA sequencing of the C3H and BALB/c alpha-skeletal actin gene promoters shows that they are virtually identical over 830 nucleotides. The relative levels of alpha-skeletal and alpha-cardiac actin proteins have been measured by N-terminal peptide analysis in the different mouse lines. The results point to regulatory loci affecting mRNA utilization and protein stability.
A developmental study of the abnormal expression of alpha-cardiac and alpha-skeletal actins in the striated muscle of a mutant mouse.
BALB/c mice possess a 5' duplication of the alpha-cardiac actin gene which is associated with abnormal levels of alpha-cardiac and alpha-skeletal actin mRNAs in adult cardiac tissue. This mutation therefore provides a potential tool for the study of the inter-relationship between the striated muscle actins. We have examined the expression of this actin gene pair throughout the development of skeletal and cardiac muscle in BALB/c mice. During embryonic and fetal development, the expression of these two genes is indistinguishable from that in normal mice, as determined by in situ hybridization. A quantitative postnatal study demonstrates that in the hearts of normal mice the level of alpha-cardiac actin mRNA declines, whereas that of alpha-skeletal actin increases. In mutant mice, these trends are exaggerated so that whereas normal mice have 95.8% alpha-cardiac mRNA and 4.2% alpha-skeletal mRNA in the adult heart, BALB/c mice have 52.4 and 47.6% of these mRNAs, respectively. This difference is also reflected at the protein level. In developing skeletal muscle, the expression of these genes follows kinetics similar to that observed in the heart with a decrease in the relative level of alpha-cardiac mRNA as the muscle matures. Cardiac actin mRNA levels are again lower in the mutant mouse, but here the effect is less striking because skeletal actin is the predominant isoform. These results are discussed in the context of the interaction between this actin gene pair in developing and adult striated muscle.
Promoter analysis of myosin alkali light chain genes expressed in mouse striated muscle.
There are three principal myosin alkali light chain (MLC) genes expressed in mouse striated muscle. The skeletal muscle gene MLC1F/MLC3F, the ventricular muscle/slow skeletal muscle gene MLC1V(MLC1S), and the atrial muscle/foetal striated muscle gene MLC1A(MLC1emb). MLC1V and MLC1A are expressed in both cardiac and skeletal muscle, and we show here that these genes use a single site of initiation of transcription, and therefore the same proximal promoter region, in both muscle types, and in myogenic cell lines in culture. We have previously shown that for the MLC1F/MLC3F gene, 1200bp of upstream sequence from the MLC1F promoter is sufficient to allow tissue specific and developmentally regulated expression. We have therefore isolated, characterised, and sequenced over 1200bp upstream of each of the three MLC genes in order to look for elements which may be involved in their regulation. Detailed comparison of their promoter sequences, as well as those of the cardiac and skeletal muscle alpha-actin genes, reveals a number of common elements. Among these is an "MLC-sequence" (CCTTTTATAG) common to all MLC genes, including those of chick and rat, and a "cardiac sequence" common to the mouse MLC1A, MLC1V and alpha-cardiac actin genes expressed in the heart.
Renal ammoniagenesis in acute hypokalemia in vivo in the dog.
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[Intra-abdominal cryptorchism. Our experience with 4 testicular autotransplantations].
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[Microsurgical treatment of varicocele in childhood].
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Actin and myosin multigene families: their expression during the formation and maturation of striated muscle.
The initial formation of skeletal muscle fibers is accompanied by the expression of muscle-type actin and myosin genes. During subsequent maturation of muscle fibers in vivo, developmental changes in the fetal/adult isoforms of these proteins occur. Skeletal muscle-specific transcripts coding for different myosin heavy chains accumulate sequentially both in vivo and in vitro. A genetic analysis demonstrates that these genes are clustered, implicating cis-acting regulatory factors. In contrast, actin and myosin light chain genes are dispersed in the mouse genome. These gene families show a different developmental "strategy": Genes expressed in adult cardiac tissue are coexpressed with the corresponding skeletal muscle sequence during fetal development. This phenomenon also occurs in adult tissue. Under conditions of cardiac overload, adult rat hearts accumulate skeletal actin mRNA and cardiac actin transcripts. In some mouse lines, a mutant cardiac actin gene locus is present. The presence of a second active upstream promoter at this locus depresses transcription of the bone fide gene, resulting in low levels of mature cardiac actin mRNA. In this situation skeletal actin gene transcripts accumulate. Genes expressed in the same fetal or adult muscle phenotype are not linked, suggesting that their coexpression is regulated by transacting factors. The promoter regions of such genes in the mouse have no common characteristics of primary structure with the exception of an E1A-type enhancer core sequence, which has a conserved 5' flanking element, seen for actin and myosin light chain genes. Reintroduction of these promoter regions into muscle cells provides a functional test for such potential regulatory sequences.
A 5' duplication of the alpha-cardiac actin gene in BALB/c mice is associated with abnormal levels of alpha-cardiac and alpha-skeletal actin mRNAs in adult cardiac tissue.
We describe the structure and transcriptional activity of the 5' portion of the alpha-cardiac actin gene of BALB/c mice. Southern blotting and DNA sequencing reveal that the promoter and first three exons of the gene are present as perfect repeats in a direct duplication of 9.5 kbp situated immediately upstream of the gene. Both promoters are active in adult cardiac tissue. Transcripts from the partial gene duplication give rise to novel RNAs that are spliced correctly in the actin region and polyadenylated. The level of mature alpha-cardiac actin mRNA is only 16.5% that found in mice that do not possess the duplication. This is due, at least in part, to interference at the transcriptional level. Transcripts from the alpha-skeletal actin gene accumulate to abnormally high levels in the hearts of such mutant mice. This result suggests tight regulatory coupling for this actin gene pair.
Comparison of three actin-coding sequences in the mouse; evolutionary relationships between the actin genes of warm-blooded vertebrates.
We have determined the sequences of three recombinant cDNAs complementary to different mouse actin mRNAs that contain more than 90% of the coding sequences and complete or partial 3' untranslated regions (3'UTRs): pAM 91, complementary to the actin mRNA expressed in adult skeletal muscle (alpha sk actin); pAF 81, complementary to an actin mRNA that is accumulated in fetal skeletal muscle and is the major transcript in adult cardiac muscle (alpha c actin); and pAL 41, identified as complementary to a beta nonmuscle actin mRNA on the basis of its 3'UTR sequence. As in other species, the protein sequences of these isoforms are highly (greater than 93%) conserved, but the three mRNAs show significant divergence (13.8-16.5%) at silent nucleotide positions in their coding regions. A nucleotide region located toward the 5' end shows significantly less divergence (5.6-8.7%) among the three mouse actin mRNAs; a second region, near the 3' end, also shows less divergence (6.9%), in this case between the mouse beta and alpha sk actin mRNAs. We propose that recombinational events between actin sequences may have homogenized these regions. Such events distort the calculated evolutionary distances between sequences within a species. Codon usage in the three actin mRNAs is clearly different, and indicates that there is no strict relation between the tissue type, and hence the tRNA precursor pool, and codon usage in these and other muscle mRNAs examined. Analysis of codon usage in these coding sequences in different vertebrate species indicates two tendencies: increases in bias toward the use of G and C in the third codon position in paralogous comparisons (in the order alpha c less than beta less than alpha sk), and in orthologous comparisons (in the order chicken less than rodent less than man). Comparison of actin-coding sequences between species was carried out using the Perler method of analysis. As one moves backward in time, changes at silent sites first accumulate rapidly, then begin to saturate after -(30-40) million years (MY), and actually decrease between -400 and -500 MY. Replacements or silent substitutions therefore cannot be used as evolutionary clocks for these sequences over long periods. Other phenomena, such as gene conversion or isochore compartmentalization, probably distort the estimated divergence time.
Alpha-skeletal muscle actin mRNA's accumulate in hypertrophied adult rat hearts.
Cardiac hypertrophy due to a chronic hemodynamic overload is accompanied by isoformic changes of two proteins of the thick filament of the sarcomere, myosin, and creatine phosphokinase. We have looked for isoactin changes, using deoxyribonucleic acid probes complementary to alpha-skeletal and alpha-cardiac actin messenger ribonucleic acids. Three groups of rats were studied at various days after application of a pressure overload (2-4 days, n = 13, 8-15 days, n = 5, and 30-40 days, n = 7) and were compared to control animals (n = 11). Whereas alpha-skeletal actin messenger ribonucleic acids were hardly detectable in the normal hearts (0.6 +/- 0.16%), they accumulated significantly in the first 4 days after the aortic stenosis (4.6 +/- 3.1%, p less than 0.001 vs. controls) and then slowly declined (8-15 days, 3.2 +/- 1.7% and 30-40 days, 1.6 +/- 0.6%, p less than 0.05 and NS vs. controls). This figure is similar to that observed in 8-day-old rats (2.27 +/- 0.3%, p less than 0.01 vs. controls). We conclude that, in rat myocardium, the expression of messenger ribonucleic acids encoding the sarcomeric actins is altered at the onset of a pressure overload hypertrophy. Although the physiological significance of isoactin changes is unknown, our results show that the thin filament participates as well as the thick filament in the response of cardiac muscle to new functional requirements.
The actin and myosin multigene families.
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Renal ammoniagenesis during acute hypoxic lactic acidosis in the dog.
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Number and organization of actin-related sequences in the mouse genome.
Recombinant plasmids containing cDNA sequences complementary to the two mouse striated-muscle actin messenger RNAs (pAF81, pAM91) and to a non-muscle actin mRNA (pAL41) have been used to examine the number and organization of actin-related sequences in the mouse genome. A large number (greater than 20) of actin-related sequences are detected on Southern blots of restricted mouse DNA, the majority of which hybridize to both the 5' and 3' ends of the actin-coding sequence, even under conditions revealing only sequences greater than 80% homologous to the actin cDNA probes. More stringent washing of these blots indicates that the two striated muscle actins are each encoded by single genes, and that a non-muscle (beta or gamma) actin cDNA detects one homologous and two closely related sequences in mouse DNA. The segregation of the two striated-muscle actin genes in recombinant inbred mouse strains shows that these genes are not closely linked (greater than 1 centimorgan), and that the skeletal muscle actin gene is not linked to a non-muscle actin gene. Screening a bank of mouse genomic DNA, cloned in Charon 4A, indicates that the number of actin-related sequences in the mouse genome is much higher than 20. In particular, five phages have been isolated representing part of a sub-family of 20 to 50 similar but non-identical sequences, only weakly homologous to actin cDNA probes (probably a family of actin pseudogenes), which are the result of a recent amplification of a greater than 17 X 10(3) base region of mouse DNA.