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A Insua

Publications and source records attributed to A Insua.

11 recordsLinked to original sources
PubMed2004

Chromosome analysis and mapping of ribosomal genes by one- and two-color fluorescent in situ hybridization in Hinnites distortus (Bivalvia: Pectinidae).

Metaphase chromosomes of the scallop Hinnites distortus were analyzed using Giemsa staining, chromosome measurements, silver staining, one- and two-color fluorescent in situ hybridization (FISH) ribosomal DNA (rDNA) probes, and 4',6-diamidino-2-phenylindole (DAPI) banding compatible with in situ hybridization. The karyotype (2n = 38) consists of three submetacentric-metacentric, one submetacentric, one subtelocentric-submetacentric, and 14 subtelocentric pairs. The 18S-28S rDNA maps at the centromeric level of two subtelocentric pairs, but not more than two nucleolus organizer region (NOR)-bearing chromosomes were transcriptionally active. The 5S rDNA seems to show a conventional tandem arrangement with a repeat unit of about 450 bp and it maps at the pericentromeric region of the long arm of one subtelocentric pair. Two-color FISH demonstrated that 18S-28S rDNA and 5S rDNA are not syntenic. Sequential FISH/Giemsa staining and subsequent chromosome pairing allow us to propose that pairs 9 and 12 carry the 18S-28S rDNA and pair 13 carries the 5S rDNA. All chromosomes are characterized as containing constitutive heterochromatin at the centromeric region. The data provided are the first contribution toward construction of the molecular karyotype of H. distortus and will be useful in assessing evolutionary relationships within scallops.

Animals↗
PubMed2002

Identification of four scallop species using PCR and restriction analysis of the ribosomal DNA internal transcribed spacer region.

Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA region spanning the 5.8S RNA gene and the 2 flanking internal transcribed spacers (ITSs) was performed to establish DNA-based molecular markers for the identification of the scallops Aequipecten opercularis, Chlamys distorta, Mimachlamys varia, and Pecten maximus. Chlamys distorta was distinguished simply by ITS size. Species-specific restriction patterns were found with the restriction enzyme AluI, and also with SmaI for A. opercularis and M. varia. When ITS sizes and the RFLPs obtained with SmaI were combined, the 4 scallops were also differentiated. Additional species-specific RFLPs were revealed after ITS-2 PCR amplification and subsequent digestion with Hsp92II. Using this marker, canned scallops were identified. Thus this work provides a simple, reliable, and rapid method for the identification of scallops that can be used when species-specific morphologic characteristics are removed or when specimens are small in size.

Journal Article↗
PubMed2001

The 5S rDNA of mussels Mytilus galloprovincialis and M. edulis: sequence variation and chromosomal location.

The 5S ribosomal DNA of the mussels Mytilus galloprovincialis and M. edulis was amplified by PCR using contiguous primers. The most general 5S rDNA amplification pattern consisted of several products in both mussels. Two main PCR products of about 250 bp and 760 bp were cloned and sequenced, revealing two classes of 5S rDNA units. These were characterized as containing an identical coding region of 119 bp but with highly divergent spacers. Clones of each unit type exhibited minimal differences except those of the large unit of M. edulis. The sequences analysed of the two mussels possess the same coding region and only six fixed base changes on the spacers. FISH, carried out with specific probes, consistently showed hybridization signals on the largest metacentric pair (two differentiated sites) and with variable frequency on two other metacentric pairs (one site on each pair). Differences in the 5S rDNA distribution between both mussels were not found. In M. edulis, chromosomes carrying 18S-28S rDNA were also identified by FISH. These correspond to two submetacentric-subtelocentric pairs, as was previously reported in M. galloprovincialis, demonstrating that the two rDNA multigene families are located on different chromosome pairs in these mussels.

Animals↗
PubMed1998

Physical mapping and activity of ribosomal RNA genes in mussel Mytilus galloprovincialis.

In bivalve molluscs, NOR analysis was carried out by silver staining, and extensive intra- and interindividual differences in the apparent number of NORs were reported. In this work, we determine the physical mapping of 18S and 28S ribosomal genes of the mussel M. galloprovincialis by fluorescence in situ hybridization (FISH). We also apply silver staining to the same individuals in order to determine if structural changes are involved in the heteromorphism detected by this technique. Our results show that rDNA loci map on the telomeric region of the long arm of two submetacentric-subtelocentric chromosome pairs. In addition to variations in NOR expression, we found some cases of structural variations that affect the number of rDNA loci between individuals and the location of the rDNA locus between the cells of the individual. We suggest that FISH should be applied to other bivalves to assess the variation of rDNA loci and undertake more accurate interspecific comparisons.

Animals↗
PubMed1998

Characterization of Aequipecten opercularis (Bivalvia: Pectinidae) chromosomes by different staining techniques and fluorescent in situ hybridization.

The chromosomes of the queen scallop Aequipecten opercularis were studied using conventional Giemsa staining, chromosome measurements, C-banding, silver staining, and fluorescent in situ hybridization (FISH) with 18S-28S rDNA and 5S rDNA probes. The karyotype (2n = 26) consists of large metacentric (pairs 1 and 2), telocentric (pairs 3, 4, 5, 6, 7, 8, and 9), and small metacentric chromosomes (pairs 10, 11, 12, and 13). The C-bands observed can be described as major and minor C-bands which are differentiated according to the intensity of the fluorescence and the frequency of the detection. Major C-bands were found on the long arm of the chromosome pairs 6, 7, 8, and 9 in an intercalary or subterminal position. Minor C-bands were located in the centromeric region in all chromosomes of the complement and also on one arm of pairs 12 and 13 in a terminal position. Silver spots were detected on the telomere of the long arms of one or two chromosomes of pair 7 in every case, although in two individuals up to four additional silver spots were detected. These were located on pairs 8 and 9 in the same position as the C-bands. 18S-28S ribosomal genes were found by FISH on the long arm of chromosome pair 7.5S ribosomal genes were located subterminally on one arm of metacentric pair 1, but two sites were differentiated in the case of elongated chromosomes. The results obtained allow for the identification of at least six different chromosome pairs in A. opercularis and contribute to the construction of an idiogram that is suitable for gene mapping and establishing accurate interspecific comparisons in scallops.

Animals↗
PubMed1995

[Effects of estrogen therapy on bone mass in postmenopausal women with osteopenia].

Estrogen treatment prevents early postmenopausal bone loss. The aim of this study was to evaluate the effects of estrogen-progestogen therapy on bone mass in elderly osteopenic postmenopausal women. Fifteen women with a mean age of 58 +/- 6 (mean +/- SD) years and 12 +/- 7 (5-31) years from menopause were evaluated. Bone mineral density (BMD) was assessed by dual X-ray absoptiometry (DXA) with 1.7% variation coefficient at lumbar spine (L2-4) and 1.9% at femur neck. Measurements were done at both sites before and after a 12 month treatment. At the beginning of the study lumbar spine BMD (LS BMD) was low: < 0.9 grs/cm2; z-score: -1.4 +/- 0.17 (mean +/- SEM). Treatment consisted in transdermal 17 beta estradiol (50 micrograms/day) (n = 10) or an equivalent natural estrogen oral dose (n = 5). Variable doses of medroxiprogesterone acetate were added on an individualized basis to women with an intact uterus (n = 12). Calcium intake was increased up to a median of 1200 mg/day (800-1600). After a one year treatment LS BMD was increased by 8.4 +/- 1.1% (mean +/- SEM) (95% CI: 6-10.8), from 0.748 +/- 0.02 to 0.810 +/- 0.02 gr/cm2 (p < 0.0001). A less marked gain in femur neck bone mineral density (FN BMD) was also noticed: 3.9 +/- 1.5% (95% CI: 0.6-7.2); 0.671 +/- 0.02 vs 0.697 +/- 0.02 gr/cm2 (p < 0.05). Patients treated with transdermal and oral routes showed similar results. Percentage variations in LS BMD and FN BMD were positively correlated (r: 0.53; p < 0.05). Six patients were treated for 2 years; LS BMD continued to rise, the additional gain being 5.1 +/- 2.2% (p < 0.05), while a non significant increase in FN BMD was observed (7.5 +/- 3.5%; p = 0.06). In the early postmenopausal period, hormonal replacement therapy (HRT) produces either a stabilization or a slight increase (2-4%) in BMD. In contrast, a significant augmentation of bone mass (especially at the spine) seems to occur in osteopenic women when THR is administered in the late postmenopausal period. This suggests that HRT could be used for the prevention as well as for the treatment of postmenopausal osteoporosis. Further studies should be done to evaluate whether HRT reduces the incidence of osteoporotic fractures in elderly osteopenic women.

Absorptiometry, Photon↗
PubMed1988

Contrasting effects of captopril and nifedipine in normotensive patients with incipient diabetic nephropathy.

Microalbuminuria is a reliable predictor of the eventual development of overt diabetic nephropathy and blood pressure is known to accelerate the course of this nephropathy. In the present studies, the effect of a 6-week treatment by placebo (n = 7), nifedipine (n = 7) and captopril (n = 8) on renal function and urinary excretion of albumin (UAE) was investigated in normotensive, insulin-dependent, diabetic patients with incipient nephropathy (UAE greater than 15 micrograms/min). No change in arterial pressure, renal function or UAE was observed in the placebo group. In response to captopril and nifedipine, mean arterial pressure decreased slightly and similarly in both groups. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) increased to a similar extent in the nifedipine group, thus resulting in no change in filtration fraction (FF). In response to captopril, GFR was unchanged whilst ERPF increased; as a consequence FF decreased. Opposite changes in UAE were observed in response to the two treatments; UAE decreased by 40% in the captopril group and by 40% in nifedipine-treated patients. These results indicate that intrarenal changes may be crucial with respect to the effect of therapy on UAE. It is suggested that only agents which reduce FF and probably intraglomerular capillary pressure, such as converting enzyme inhibitors, alter UAE and may possibly interfere with the course of incipient diabetic nephropathy in normotensive patients.

Adolescent↗
PubMed1988

Comparative effect of captopril and nifedipine in normotensive patients with incipient diabetic nephropathy.

The effect of a six-week treatment by placebo, the calcium channel blocker nifedipine or the converting enzyme inhibitor captopril was assessed in normotensive patients with insulin-dependent diabetes and incipient nephropathy. In response to captopril and nifedipine, arterial pressure decreased slightly and to a similar extent. These drugs resulted in opposite effects on urinary albumin excretion (increase in urinary albumin excretion by 40% during nifedipine and decrease by 40% during captopril treatment). No change in urinary albumin excretion was observed in the placebo group. This observation of opposite changes in urinary albumin excretion in the presence of a similar fall in arterial pressure suggests that the effect of captopril and nifedipine on urinary albumin excretion results from some difference in their intrarenal action.

Adult↗
PubMedDate not supplied

Comparative effect of captopril and nifedipine in normotensive patients with incipient diabetic nephropathy.

In these studies, the effect of a 6-wk treatment by placebo, the calcium-channel blocker nifedipine, or the converting-enzyme inhibitor captopril was assessed in normotensive patients with insulin-dependent diabetes and incipient nephropathy. In response to captopril and nifedipine, arterial pressure decreased slightly and to a similar extent. These drugs resulted in opposite effects on urinary excretion of albumin [i.e., increase in urinary albumin excretion (UAE) by 40% during nifedipine treatment and decrease by 40% during captopril treatment]. No change in UAE was observed in the placebo group. This observation of opposite changes in UAE in the presence of a similar fall in arterial pressure suggests that the effects of captopril and nifedipine on UAE result from some difference in their intrarenal action. The data do not present recommendations for the use or disuse of captopril or nifedipine in such a group of patients and do not allow extrapolation to hypertensive diabetic subjects well controlled by other conventional antihypertensive agents.

Adult↗