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Biomedical subjects

A Serra

Publications and source records attributed to A Serra.

At least 199 records · Page 11Linked to original sources
PubMed1990

Molecular study of parental origin of extra chromosome 21 in regular and de novo translocation trisomies.

The parental origin of the extra chromosome 21 (or extra 21q) was determined in seven informative families with a Down syndrome (DS) child by using molecular polymorphisms. Five DS patients had regular trisomy, one a de novo 14/21 translocation and another a de novo 21/21 translocation or isochromosome 21q. In four families with regular trisomy, the extra chromosome was of maternal origin, and in one family it was paternally derived. In the two families with a de novo aberration, both the 14/21 translocation and 21/21 rearrangement originated during maternal meiosis. For a better evaluation of the stage of meiotic error and the occurrence of crossovers between nondisjoined chromosomes, the regional map position of four of the nine informative DNA markers, used in this study, was refined, leading to useful localizations in both centromeric and distal regions. Recombination events were found in two families with regular trisomy, one occurring between chromosomes 21 that failed to disjoin at maternal meiosis I, the other prior to a paternal meiosis II nondisjunction.

Blotting, Southern↗
PubMed1990

Pericentric inversion of chromosome 9: prevalence in 300 Down syndrome families and molecular studies of nondisjunction.

The incidence of Down syndrome (DS) families where one of the parents is an heterozygous carrier of pericentric inversion of the heterochromatic region of chromosome 9-inv(9) (qh) - was determined in 3 independent groups of 100 families each. The total number of 17 such families found in the sample is significantly greater than the expected number of 5.73 for a sample of non-DS families of equal size. Consequently, the statistical association of the presence of inv (9) (qh) in one parent with the birth of a DS offspring, and the correlative 3-fold increased risk of a DS child for such families, seem to be demonstrated. A study of the origin of nondisjunction, using restriction fragment length polymorphism (RFLP) segregation analysis with a sufficient number of chromosome 21 specific probes, has provided complete information in 7 of 8 available families. Although the statistical interpretation of the results is not straightforward, due to the small size of the sample, the observed data do not contradict the assumption that the presence of inv (9) (qh) in a parent increases, by a factor of about 3, the chance that the offspring will inherit an extra chromosome 21 from that parent. Nevertheless, gathering further data appears desirable because stronger evidence would have relevance both for clinical implications and for the understanding of the function of heterochromatin, particularly with respect to meiotic and mitotic processes.

Chromosome Inversion↗
PubMed1990

Acrocentric chromosome double NOR is not a risk factor for Down syndrome.

Jackson-Cook et al. (American Journal of Human Genetics 37:1049-1061, 1985) predicted a high risk of Down syndrome (DS) children for parents carrying a double NOR on acrocentric chromosomes. Hassold et al. (Human Genetics 76:381-384, 1987) could not confirm Jackson-Cook et al.'s findings, thus casting doubts on their conclusions. We studied the NORs of 1) 60 parents of 30 unselected DS subjects; 2) 30 unselected healthy subjects without trisomic offspring, who asked for chromosome analysis; and 3) 100 slides randomly chosen among 1,000 prepared by routine standard techniques and belonging to subjects who were chromosomally normal. By applying rigorously established techniques and scoring criteria we found 4 subjects (6.7%) with strictly defined double NORs (dNORs) in the DS parents sample, 2 subjects (6.7%) in the first control sample, and 3 (3%) in the second control sample. No significant difference among the observed frequencies of dNORs in the 3 samples could be demonstrated. Therefore, our data do not support Jackson-Cook et al.'s statements on the association of dNOR carrier status with DS offspring and on a highly increased risk of meiotic nondisjunction of chromosome 21 for a dNOR carrier parent. A tentative interpretation of the apparently contrasting cytogenetic findings would indicate that sampling and assignment biases are the main causes of this discrepancy.

Case-Control Studies↗
PubMed1990

Analysis of the autoagglutination phenomenon, serogroup and hydrophobicity as virulence markers in mesophilic aeromonads isolated from stool cultures.

The autoagglutination phenomenon (AA) was studied in 71 strains of mesophilic aeromonads isolated from stool cultures of patients with acute diarrhea (28 Aeromonas hydrophila, 20 Aeromonas sobria, and 23 Aeromonas caviae). Two phenotypes were considered in the AA+ strains: SP+ (self-pelleting) and PAB+ (precipitation after boiling). Serogrouping of the strains was performed only with the 0:11 serum. Other properties studied were agglutination with acriflavine (Acr) and crystal violet uptake (CVB). Phenotype AA+ was found in 29.5% of the strains; 7% of these AA+ strains exhibited the SP+ PAB+ pattern and 22.5% the SP- PAB+ pattern. The species Aeromonas hydrophila comprised the highest proportion (28.5%), and Aeromonas caviae the lowest (13%). Fifty percent of the PAB+ strains of Aeromonas hydrophila and Aeromonas sobria belonged to serotype 0:11. None of the PAB+ strains of Aeromonas caviae belonged to this serotype. 8.4% of the strains were Acr+ and 23.9% CVB+.

Acute Disease↗
PubMed1990

Risk stratification and prognosis of patients with recent onset angina.

We prospectively assessed coronary artery disease and natural history in a series of 104 patients (99 males, mean age 52 +/- 8 years) admitted with recent onset angina (defined as a history of angina of less than 1 month duration). Coronary angiography showed one-vessel disease in 31, two-vessel disease in 22 and three-vessel disease in 14; 37 patients had normal coronary arteries. After a mean follow-up of 36 (range 1 to 52) months, one patient died, 13 sustained a myocardial infarction and 21 underwent surgery. The univariate analysis showed four of 12 clinical features derived from clinical history and data from CCU (exertional angina (P less than 0.001), and recurrence of angina (P less than 0.05)) to be associated with the presence of coronary artery disease. These clinical features were termed clinical risk characteristics. Three-year probability of medical events (death or acute myocardial infarction) for patients with 0-1 clinical risk characteristics was 0 and that of combined events (need for revascularization with or without a preceding medical event) 0.11, whereas patients with 2 or more risk characteristics had probabilities of 0.27 and 0.49, respectively. Multivariate analysis identified the number of clinical risk characteristics as the only independent predictor of medical events (P less than 0.002) and a positive thallium stress test (P less than 0.0001), the number of clinical risk characteristics (P less than 0.002) and the number of involved arteries (P less than 0.002), as independent predictors of combined events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Left-to-right atrial shunting after percutaneous mitral valvuloplasty. Incidence and long-term hemodynamic follow-up.

To assess the incidence and long-term evolution of left-to-right atrial shunting (AS) after the performance of percutaneous mitral valvuloplasty (PMV), venovenous indicator dilution curves and right heart oximetric measurements were obtained in 68 consecutive patients before and after successful PMV. The procedure increased the mitral valve area (p less than 0.0001) and decreased the mitral gradient (p less than 0.0001). No AS was detected before PMV, but it was detected immediately after PMV. Oximetry identified AS in 17 patients (25%), and dilution curves identified AS in an additional 25 (total, 62%). The ratio of mean pulmonary to systemic blood flow (Qp/Qs) was 1.31 +/- 0.2, and in six patients (9%), the ratio was 1.5 or greater. Among nine clinical, 20 hemodynamic, and six procedural variables, stepwise logistic regression analysis selected the following as independent predictors of AS: smaller increases in valve area (p = 0.01) after PMV, absence of previous surgical commissurotomy (p = 0.02), mitral valve calcification (p = 0.02), and smaller left atria (p = 0.06). Among the 33 patients recatheterized at 6 months, oximetry had detected AS in 10, and dilution curves detected AS in an additional nine (total, 58%) immediately after PMV. At 6 months, AS had decreased or disappeared in 14 of these patients (74%), had increased in three (16%), and was unchanged in two (10%). Overall, at 6 months, oximetry identified AS in three patients, and dilution curves identified AS in an additional 13 (total, 48%). AS was detected at 6 months in only three patients but was not detected immediately after PMV. Although AS is very frequent immediately after PMV, Qp/Qs is usually less than 1.5. The appearance of shunting correlates with patient characteristics and with less improvement in valve area after PMV. Atrial shunting usually persists at 6 months, but its severity almost always decreases.

Blood Circulation↗
PubMed1990

Vascular atherosclerotic disease: evaluation of the whole-blood filterability and red cell membrane microrheological pattern after intravenous administration of a single dose of pentoxifylline.

A study was carried out in 10 patients with vascular atherosclerotic disease to investigate the effects of a single dose of 300 mg pentoxifylline, given by intravenous infusion over 30 minutes, on various macrorheological and microrheological parameters. Measurements were made at baseline, at the end of the intravenous infusion and again 30 minutes later, of whole-blood filterability, erythrocyte membrane fluidity (using pyrene as probe) and transverse fluidity gradient (using fluorescent fatty acids as probes). The results showed that there was a significant variation in whole-blood filterability and the red cell membrane fluidity gradient after pentoxifylline. No difference, however, was noted for the membrane fluidity. These data suggest, therefore, that pentoxifylline plays a role in affecting the red cell membrane microrheological pattern.

Aged↗
PubMed1990

A 3' truncation of MYC caused by chromosomal translocation in a human T-cell leukemia increases mRNA stability.

The proto-oncogene MYC is rearranged at its 3' end in the human T-cell leukemia line Hut 78 as a result of a translocation between the long arms of chromosomes 8 and 2. The nucleotide sequence at the breakpoint shows that the rearranged allele of MYC is truncated 24 nucleotides before the first poly(A)-addition signal. The 3' truncated MYC lacks a 61 nucleotide AT-rich sequence that has been reported to mediate selective mRNA degradation. We show that the truncation results in prolonged stability of MYC mRNA: the half life of the MYC mRNA in Hut 78, as well as in Rat 1A cells transfected with the truncated allele of MYC is increased by at least 5-fold. Our results document yet another mechanism by which MYC may be rendered pathogenic and dramatize the importance of mRNA stability in the regulation of MYC activity.

Base Sequence↗
PubMed1990

[Effects of tiaprofenic acid on nasal mucociliary transport time].

Mucociliary activity is a fundamental aspect of the clearance function of the respiratory tract; mucociliary transport time being the easiest parameter to record in regard to the overall, more complex function of nasal clearance. A double blind, multicenter randomized study was carried out on 40 rhinopathy patients divided into two groups and treated with tiaprofenic acid 300 mg or a placebo twice a day for seven consecutive days. Before and after treatment the following were recorded: subjective and objective nasal MCT time, using an original composition of vegetable charcoal powder and saccharin powder at 3%; nasal obstruction. The authors conclude that the treatment of rhinitis with tiaprofenic acid improved not only the clinical symptomatology but also the mucociliary transport time and rhinomanometric examination.

Adolescent↗
PubMed1990

Human meibomian glands: a histochemical study for androgen metabolic enzymes.

Human meibomian glands were treated for the histochemical demonstration of several enzymatic activities. The 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) appeared intensely reactive in the differentiating excretory cells, and weakly reactive in the basal cells and in the epithelial cells of the proximal portion of the ducts. The results indicate that meibomian glands can metabolize androgens by the reductive pathway, characteristic of target tissues. The finding of an intense reactivity for the enzymes glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) is also discussed.

Adolescent↗
PubMed1990

Total red cell Ca2+ content and rheological determinants in a group of subjects with vascular atherosclerotic disease.

We evaluated the total red cell Ca2+ content and the macro- and microrheological determinants in a group of subjects with vascular atherosclerotic disease (VAD). From the results obtained it is evident that, compared to controls, the VAD group presents an alteration of the macro- and microrheological parameters. No difference is evident for the red cell Ca2+ content in normals and in VAD subjects. No relationship is present between total red cell Ca2+ content, VBC (volume blood cells), MEA (mean erythrocyte aggregation) and red cell membrane fluidity expressed as Iex/Im ratio. In contrast to the latter, are the correlation between the red cell Ca2+ content and the degree of polarization obtained with fatty acid probes.

Aged↗
PubMed1989

N-ras mutations in myeloid leukemias.

The presence of mutations activating the N-ras gene was investigated by the polymerase chain reaction technique in twenty patients with acute myeloblastic leukemia (AML) at onset and in four patients with Ph1 positive chronic myelogeneous leukemia (CML) either in chronic phase or in blast crisis. Four remission samples and four relapses from the AML cases were also studied. Mutations were found in five out of twenty (25%) untreated AML cases at onset. No mutations were detected in the complete remission samples, two of them with N-ras mutations during the leukemic phase. Two out of the four leukemia relapses were positive for the same N-ras mutation shown at presentation, whereas no new mutations were found in the other two initially negative cases. An N-ras mutation appeared during the blast crisis of one of the four CML, which were all negative during the chronic phase. In conclusion, whereas some data appear to be consistent with a role of the N-ras mutations as initiating events in myeloid leukemias, in other cases N-ras activation seems to represent a factor involved in progression. These data suggest that a partial overlapping between initiation and progression factors could exist in naturally occurring tumors.

Codon↗
PubMed1989

Catalase and glutathione peroxidase activity in cells with trisomy 21.

CuZnSOD is produced in overdose in cells with trisomy 21. This has been considered to be a cause of increased oxidative stress. In the present work we have studied the catalase and glutathione peroxidase activity in fibroblasts from 6, and blood cells from 30, subjects affected by Down syndrome. In the fibroblasts, catalase and glutathione peroxidase activities did not differ significantly from control cells. In platelets, lymphocytes, polymorphs and erythrocytes, no significant increase of catalase activity was found while glutathione peroxidase activity appeared significantly increased in platelets, polymorphs and erythrocytes but not in lymphocytes. These data seem to indicate that the increase of CuZnSOD in trisomy 21 cells does not affect the production of catalase. An increase, instead, of glutathione peroxidase has been detected in all blood cells, except in lymphocytes; this is a sign of a greater need for protection against the risk of lipoperoxidation. The fact that the enhancement of glutathione peroxidase activity could be assessed only in some types of cells examined suggests that the observed increase in those cells is probably a result of an additive effect of the overproduction of CuZnSOD due to gene dosage and the ordinarily higher content of oxygen radicals and peroxides.

Adolescent↗
PubMed1989

Molecular characterization of Italian chromosomes carrying the Lepore Boston gene.

Hemoglobin Lepore Boston is characterized by abnormal non-alpha-chains that are the product of a fusion delta beta gene originated from an unequal crossing over between misaligned delta and beta genes. The investigation of the restriction fragment length polymorphisms (RFLP) of the beta-globin gene cluster in 18 Italian Lepore Boston chromosomes indicates that the hybrid gene is linked to two RFLP patterns. The majority of chromosomes show a pattern which corresponds to haplotype V and a minority to haplotype I according to Orkin's classification. A single Hb Lepore Boston homozygote was homozygous for haplotype V. The two haplotypes differ only for a single site 3' to the beta cluster. Our data allow the speculation that in Italy the Lepore Boston gene might be the result of multiple recombination events.

Chromosome Deletion↗