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R Coco

Publications and source records attributed to R Coco.

At least 19 recordsLinked to original sources
PubMed2004

A constitutional complex chromosome rearrangement involving meiotic arrest in an azoospermic male: case report.

Complex chromosome rearrangements are rare aberrations that frequently lead to reproductive failure and that may hinder assisted reproduction. A 25-year-old azoospermic male was studied cytogenetically with synaptonemal complex analysis of spermatocytes from a testicular biopsy and fluorescence in situ hybridization (FISH) of lymphocytes. The spermatocytes showed a pentavalent plus a univalent chromosome. Cell death occurred mainly at advanced pachytene stages. The sex chromosomes were involved in the multiple, as shown by their typical axial excrescences. Two autosomal pairs, including an acrocentric chromosome (15), were also involved in the multiple. FISH allowed the definite identification of all the involved chromosomes. An inverted chromosome 12 is translocated with most of one long arm of chromosome 15, while the centromeric piece of this chromosome 15 is translocated with Yqh, forming a small marker chromosome t(15;Y). The euchromatic part of the Y chromosome is joined to the remaining piece of chromosome 12, forming a neo-Y chromosome. The patient shows azoospermia and a normal phenotype. The disruption of spermatogenesis is hypothetically due to the extent of asynaptic segments and to sex-body association during pachytene. This CCR occurred 'de novo' during paternal spermatogenesis. Meiotic analysis and FISH are valuable diagnostic tools in these cases.

Adult↗
PubMed2003

[Retinal shortening: the most severe form of proliferative vitreoretinopathy (PVR)].

PURPOSE: To identify the clinical characteristics of patients developing retinal shortening due to intraretinal PVR. METHODS: Observational and retrospective cohort study on 110 PVR patients operated on between 2000 and 2001. During surgery, after removing epiretinal membranes and ruling out the presence of subretinal membranes, a perfluorocarbon liquid was injected. Those cases in which retinal flattening was not accomplished, were considered intraretinal PVR (group 1). Those in which retinal flattening allowed endolaser application, were taken as the control group (group 2). Clinical features of both groups were compared by chi-square test. RESULTS: 60 cases (54.5%, CI 95%: 40.5-68.5) showed retinal shortening (group 1). In 24 cases (21.8%, CI 95%: 12.9-30.7) complete retinal flattening was accomplished (group 2). In 26 cases (23.6%), evaluation was inconclusive. In 9 out of the 60 cases of group 1 (15%) a retinectomy was necessary to reattach the retina. Differences between both groups were not statistically significant for any of the clinical variables. However, the number of retinal detachments of more than 60 days of evolution was significantly higher in retinectomized eyes (20.7%) than in group 1 (3.7%) (p=0.04). CONCLUSIONS: Retinal shortening is a relatively frequent phenomenon in PVR. Further studies are necessary to characterize this clinical presentation of PVR and its pathogenesis.

Case-Control Studies↗
PubMed1996

High-performance liquid chromatographic determination of vancomycin in rabbit serum, vitreous and aqueous humour after intravitreal injection of the drug.

A high-performance liquid chromatographic method for the determination of vancomycin in rabbit serum, vitreous and aqueous humour has been developed. No clean-up step was necessary for vitreous and aqueous humour samples. For serum samples liquid-liquid and solid-phase extraction were tested and the best results were achieved using C18 cartridges. The extracts were analyzed on a C18 reversed-phase column, using a mixture of 0.05 M phosphate buffer (pH 4) with 10% of acetonitrile as mobile phase. The detection was carried out at 198 nm, which allows higher sensitivity. The average quantitation limit obtained was 0.03 micrograms/ml. The method has been applied to the study of the residual quantities of vancomycin in serum and rabbit eyes after intravitreal administration of the drug in endophthalmitis treatment.

Animals↗
PubMed1995

Brief clinical report: interstitial deletion of the long arm of chromosome 4, del(4)(q28-->q31.3).

Interstitial deletions of the long arm of chromosome 4 are rare. Different breakpoints are involved. Only one of the patients had a very similar deletion to that of the present case. Both had low birth weight at term; weight, length and head circumference less than the third centile; epicanthic folds; apparently low-set abnormal ears; broad nasal bridge; micrognathia; hypoplastic nails; delayed psychomotor development; and mild mental retardation.

Abnormalities, Multiple↗
PubMed1992

[Validity of the proximal isovelocity surface area color Doppler method for calculating the valve area in patients with mitral stenosis; comparison with the two-dimensional echocardiographic method].

BACKGROUND: The proximal isovelocity surface area (PISA) method, assessed by color Doppler echocardiography, has gained acceptance as a means of calculating flow rate through regurgitant orifice. The method can also be used to derive mitral valve area (MVA), by continuity equation, in patients with mitral stenosis (MS). The aim of this study was to compare the PISA method with the two-dimensional echocardiographic planimetry (2D) method and pressure half-time method (PHT) in MVA calculations in a group of 37 patients with MS. METHODS AND RESULTS: All of these patients had satisfactory MVA by 2D method. There were 22 female and 15 male; age 56 +/- 11 years (range 32-71); 19 were in sinus rhythm (SR) and 18 in atrial fibrillation (AF); 17 patients had pure MS, while the remaining 20 had associated mitral regurgitation (MR); in 23 patients the orifice morphology was circular or elliptic, and was defined as regular; while in 14 patients the morphology was irregular for the presence of two or more nodular calcifications on the commissures or leaflet's edges. MVA by PISA method was calculated assuming a uniform radial flow convergence region along a hemispherical surface, according to the formula: MVA = 2 pi r2 Vn(1-cos theta)/Vmax; where r was the PISA radius measured in 2D from the first alias to the mitral leaflet's edge; Vn was the flow velocity at radial distance from the mitral orifice; Vmax was the peak transmitral velocity by CW Doppler; 1-cos theta was a factor that accounted for the inflow angle formed by the mitral leaflets. The Nyquist limit was lowered to 29 cm/sec. Alpha angle formed by the mitral leaflets ranged between 86 degrees and 134 degrees; average 110 degrees +/- 10 degrees. 2D MVA was 1.33 +/- 0.37 cm2; range 0.69-2.2 cm2; PHT MVA was 1.29 +/- 0.34 cm2; range 0.70-2.1 cm2; PISA MVA was 1.18 +/- 0.36 cm2; range 0.47-1.95 cm2. The PISA method underestimates MVA by 0.15 +/- 0.21 cm2, in comparison with the 2D method; and by 0.11 +/- 0.18 cm2 in comparison with PHT method (p ns). The correlation between 2D and PISA MVA was: r = 0.84; p < 0.001; y = 0.83x + 0.06; 95% confidence intervals +/- 0.40 cm2; and between PHT and PISA MVA was: r = 0.79; y = 0.84x + 0.09; p < 0.001; 95% confidence intervals +/- 0.46 cm2. The correlation coefficient was similarly good in patients with SR or AF, and did not significantly change in patients with pure MS or MS+MR; neither did it vary with respect to the orifice morphology (p < 0.001 for all the variables considered), except for the correlation PHT-PISA in the group of patients with irregular orifice morphology (r = 0.70; p = 0.005). The interobserver and intraobserver variability were, respectively: 2.2% and 4.4% for 2D MVA; 3.4% and 3.8% for PHT MVA; 5.2% and 3.5% for the PISA radius; 6.1% and 4.4% for the alpha angle; 10.2% and 7.2% for PISA MVA (F ratio of variances ns). CONCLUSIONS: In conclusion, the PISA method allows accurate assessment of MVA in patients with MS, regardless of cardiac rhythm or additional MR. Moreover, our study suggests that orifice morphology does not affect the accuracy of this method.

Adult↗
PubMed1987

X-radiation-induced chromosome breakage in retinoblastoma lymphocytes.

We have examined the spontaneous and X-radiation-induced chromosomal damage in normal humans and in patients with retinoblastoma using the BudR-Giemsa technique in lymphocytes cultured for 48 h. 9 sporadic unilateral non-hereditary cases, 11 hereditary cases (8 bilateral sporadic and 3 unilateral hereditary cases) and 20 healthy individuals were studied simultaneously. No difference in the spontaneous frequency of chromatid and chromosome aberrations was observed between patients and controls. After treatment with 150 rad the frequency of chromosome exchange aberrations was higher in unilateral hereditary cases than the controls (42.0% +/- 5.3 and 22.3% +/- 2.6 respectively; p = 0.05). In bilateral sporadic retinoblastoma 2 different groups were observed. A hypersensitive group showed a significant increment in radiation-induced chromosomal exchange aberrations over the control group (46.2% +/- 5.4 and 24.2% +/- 2.1 respectively; p = 0.01). The other group had a chromosomal exchange frequency similar to normal individuals (26.5% +/- 2.0 and 24.2% +/- 0.4 respectively; p = 0.10). Sporadic unilateral non-hereditary retinoblastoma had an exchange chromosomal aberration frequency similar to control individuals (26.1% +/- 2.8 and 24.6% +/- 2.7 respectively; p greater than 0.10). These results suggest that: There is no relationship between spontaneous chromosome fragility and retinoblastoma. Sporadic unilateral non-hereditary retinoblastoma has normal chromosome sensitivity to X-irradiation. Some hereditary cases of retinoblastoma are sensitive to X-rays while others behave like normals. A mutation or a submicroscopic deletion at a DNA repair locus which is independent of the retinoblastoma gene may cause this radiosensitivity.

Cells, Cultured↗
PubMed1986

Chromosomal sensitivity to X-rays in lymphocytes from patients with Turner syndrome.

Lymphocytes from patients with Turner syndrome were irradiated with X-rays (200 rad) to determine the chromosomal aberration frequency in first-division metaphases. Five patients with 45,X karyotype; three 45,X/46,Xi(X)q mosaics; one 45,X/47,XXX mosaic and 9 female controls were studied. Patients with a 45,X karyotype exhibited a radioinduced chromosomal aberration frequency similar to controls (38.6 +/- 6.37 and 36.2 +/- 5.11 respectively; p = 0.42). In the mosaics, 45,X cells had a mean frequency of 38.75 +/- 2.16; 46,Xi(X)q cells a mean of 38 +/- 2.16 and the control group a rate of 36.25 +/- 4.32. No differences were observed between 45,X and 46,Xi(X)q cells (p = 0.50), 45,X and normal cells (p = 0.24) or 46,Xi(X)q and normal cells (p = 0.35). Apparently neither the X monosomy nor the Xq isochromosome influences the 'in vitro' X-ray-induced chromosomal damage in Turner syndrome lymphocytes.

Cells, Cultured↗
PubMed1983

Effect of metformin on blood glucose, insulin and C-peptide responses to glucagon in non-insulin dependent diabetics.

Since the C-peptide Radioimmuno active/Immuno Reactive Insulin (CPR/IRI) molar ratio is considered as an index of insulin hepatic extraction and tissue receptor binding, the AA. investigated the effects of metformin on this index after glucagon infusion in non-insulin dependent diabetics. Fourteen lean subjects (aged 48 to 67 years, mean 54 +/- 7) with non-insulin dependent diabetes were studied. At 9.00 a.m. each subject after overnight fasting, underwent glucagon infusion (1 mg i.v. diluted in 250 ml of saline, infused at a rate of 8.3 gamma/min for 2 hours); blood specimen were obtained at --15, 0, 30, 60, 90, 120 min. This test was repeated after a five-day treatment with metformin (1.5 g per os). For each sample plasma glucose by glucose oxidase method, plasma insulin and C-peptide by Radio Immuno Assay (RIA) method were determined. After treatment with metformin the hyperglycemia induced by glucagon was not influenced; nevertheless insulin and C-peptide plasma levels showed an evident reduction while CPR/IRI molar ratio was unchanged. The AA. suppose an indirect effect of metformin upon beta cells, namely a less pancreatic insulin requirement, mediated by an improvement of glucose utilization.

Aged↗
PubMed1982

Cytogenetic findings in 200 children with mental retardation and multiple congenital anomalies of unknown cause.

We report a cytogenetic study of 200 children with mental retardation and three or more major or minor congenital anomalies. In all cases, the chromosomes were studied with conventional staining methods (nonbanding) and with at least one of the following techniques: Q, G, or R banding. In a few patients, C banding and in vitro differentiation with BUDR and acridine orange (R banding) were also used. In patients with structural abnormality, parental chromosomes were studied using the same techniques. A chromosomes abnormality was found in 42 patients (21%). Of these, 16(8%) had complete or mosaic aneuploidies (11 autosomal and 5 gonosomal); and 26 (13%) had structural defects. In 21 of the latter the structural abnormality occurred as a de novo rearrangement, and in 5 the defect was inherited from a parent carrier of a balanced rearrangement. The contribution of chromosome aberrations to the cause of (idiopathic) MCA/MR syndromes is discussed.

Abnormalities, Multiple↗
PubMed1981

Fetal phenotype in a case of partial trisomy 21 and partial monosomy 22 detected prenatally.

Prenatal diagnosis was performed in a woman whose previous pregnancy resulted in a girl with probable Down syndrome who died soon after delivery. The mother was found to be a carrier of a reciprocal balanced translocation between chromosomes 21 and 22, and the fetus was found to have an unbalanced translocation involving chromosomes 21 and 22: 46,XX, -22, +t(21;22)(q22;q11)(21 pter leads to 21q22::22q11 leads to 22qter). Despite partial monosomy for the proximal segment of 22 and trisomy for proximal 21, the fetus did not have gross external abnormalities, but several internal malformations were found. To our knowledge, this is the first time that this unbalanced karyotype has been described.

Abnormalities, Multiple↗