Search PubMed⌕ Search

Biomedical subjects

A Serra

Publications and source records attributed to A Serra.

At least 253 records · Page 14Linked to original sources
PubMed1985

Erythrocyte catechol-O-methyltransferase activity: genetic analysis in nuclear families with one child affected by Down syndrome.

Erythrocyte catechol-O-methyltransferase (COMT) activity was measured in 142 members of 32 nuclear families in which one child had Down syndrome (DS). The mean activity in subjects with trisomy 21 appears higher than in parents and sibs, though not significantly so. However, this fact does not seem to modify the properties expected for a trait genetically controlled in a diploid population. The commingling analysis of the COMT activity in the whole group, and in each subgroup of relatives, suggests a mixture of two or, more likely, three components, the latter being in agreement with a transmission model of genes without dominance. The most parsimonious hypothesis supported by the mixed model segregation analysis is that of an additive major locus (d = 0.5) with an estimated frequency of 0.40 +/- 0.03 for the COMTH gene, to which a small polygenic effect (H = 0.067) can be added. This hypothesis is supported further by the analysis of family resemblance, r = 0.45 +/- 0.12 being the maximum likelihood estimator of the intraclass correlation among sibs. The higher COMT activity in DS subjects may reflect a situation of general enzyme disorder only indirectly connected with trisomy of chromosome 21.

Catechol O-Methyltransferase↗
PubMed1985

A 45,X male with evidence of a translocation of Y euchromatin onto chromosome 15.

A 19-year-old male with azoospermia was found to have a 45,X karyotype with additional euchromatic material on 15p. The parents' karyotypes are normal. The cytogenetic data, the positive H-Y-typing, and the presence of Yp-specific restriction fragments detected in the proband's genome by molecular DNA probes suggest that the short arm of the Y chromosome, including part of the centromere, is translocated onto the nucleolus organizer region (NOR) of chromosome 15.

Adult↗
PubMed1985

Coordinate expression of MnSOD and CuZnSOD in human fibroblasts.

The amount of manganese superoxide dismutase (MnSOD) and the activity of copper-zinc superoxide dismutase (CuZnSOD) have been studied in five karyotypically normal human fibroblast strains, using nuclear magnetic resonance (NMR) and polarographic methods. A significant correlation between the two enzyme activities, and a linear increase of MnSOD with the increase of CuZnSOD have been demonstrated. Both enzymes are present in nuclei, mitochondria, lysosome-microsome fraction and cytosol. These findings suggest that the two enzymes dismutate the O-2 cooperatively and that a common genetic control maintains the relative amounts of the two enzymes constant.

Adolescent↗
PubMed1985

Coordinate expression of Mn-containing superoxide dismutase and Cu,Zn-containing superoxide dismutase in human fibroblasts with trisomy 21.

The amount of Mn superoxide dismutase (MnSOD) and the activity of Cu,Zn-superoxide dismutase (CuZnSOD) have been studied in human fibroblasts of five subjects with trisomy 21 and five subjects with normal karyotype, using nuclear magnetic relaxation and polarographic methods. In the trisomic fibroblasts we have found a mean molar amount of MnSOD 25.4% lower than in the control, and an amount of CuZnSOD 54.7% higher. A positive significant correlation between the activities of both enzymes has been observed indicating that the two enzymes dismute the O2- cooperatively. However, the increase of MnSOD per unit of CuZnSOD appears significantly lower in the trisomic fibroblasts, an effect that is not due to a diminished inducibility of MnSOD. These findings suggest that the MnSOD and CuZnSOD genes interact to preserve the normal level of total SOD activity.

Adolescent↗
PubMed1984

Estrogens antagonize apomorphine-induced yawning in rats.

The administration of a small dose of apomorphine (50 micrograms/kg s.c.) induced repeated episodes of yawning in male rats. Short-term (3 days) treatment with 17 beta-estradiol antagonized apomorphine-induced yawning in male rats. Moreover, apomorphine induced yawning much less effectively in female than in male rats. These results suggest that both endogenous or exogenously administered estrogens induce subsensitivity of the DA receptors mediating yawning in rats.

Animals↗
PubMed1984

Vasculitis affecting the kidney: presentation, histopathology and long-term outcome.

Fifty-three patients who by clinical and/or histological criteria were judged to have vasculitis affecting the kidney were reviewed. Patients with systemic lupus or Schönlein-Henoch purpura were excluded. Segmental necrotising glomerulitis was taken as a manifestation of vasculitis ('microscopic polyarteritis'). Those patients in whom vasculitis was confined to glomerular capillaries were compared with those who in addition had vascular lesions outside the glomeruli. The two groups were found to have identical clinical features. Clinical presentation was predominantly extrarenal, and exclusively renal in only two. Three patients were classified histologically as Wegener's granulomatosis, four had malignant tumours and two relapsing polychondritis. Hepatitis B surface antigen was absent in all of 37 patients tested. Renal disease presented with microscopic haematuria and minor proteinuria in the majority (32) but 16 patients presented with rapid deterioration of renal function, including seven with anuria. Histologically 42 patients showed segmental necrotising glomerulitis ('microscopic polyarteritis'), six diffuse proliferative glomerulonephritis,and in five only minor or ischaemic glomerular changes were present. Crescents were found in 41/42 of those with segmental necrotising glomerulitis, nd involved more than 50 per cent of glomeruli in 15 patients. Immunohistochemical studies were generally negative except the fibrin. Electron microscopy showed no evidence of immune deposits in necrotising glomerulitis, but these were present in 2/6 patients with diffuse proliferative glomerulonephritis. Overall prognosis was poor, 35 patients having died, 20 early in the course of the disease and 15 later. Oligoanuria and extensive crescent formation were adverse signs. Survivals were 54, 38 and 34 per cent at one, five and 10 years respectively. Of those who survived the initial illness, 12 were stable with apparently inactive disease, whilst 16 continued to show clinical signs of activity and required treatment. A variety of treatments was employed including oral and intravenous corticosteroids, immunosuppressive agents, anticoagulants; only one patient was treated by plasmapheresis. It is difficult to draw any firm conclusions as to the efficacy of treatment and survival rates remain unsatisfactory.

Acute Disease↗
PubMed1983

A boy with ring chromosome 15 derived from a t(15q;15q) Robertsonian translocation in the mother: cytogenetic and biochemical findings.

We describe a boy with a ring chromosome 15, showing the manifestations characteristic of this condition, ie, growth deficiency and unusual facial appearance with minor anomalies. The ring was derived from a t(15q;15q) chromosome of the mother, who had also had four spontaneous abortions. The respective karyotypes were 45,XX, -15,-15,+t(15q;15q) (mother) and 46,XY,-15,+r(15q;15q)mat (15q13 leads to cen leads to 15q26)(son). The ring chromosome lacked the short arms of the two translocated chromosomes 15 and was duplicated for a portion of the long arms near the centromere, probably cen leads to q13. Data from enzyme assays suggest that this duplicated region carries the alpha-mannosidase gene.

Adult↗
PubMed1983

Reproductive risks for translocation carriers: cytogenetic study and analysis of pregnancy outcome in 58 families.

Here we report on studies of the reproductive risks for heterozygous carriers of chromosome translocations. Pregnancy outcome, breakpoints, mode of segregation of the translocated chromosomes, and resulting chromosome imbalance were analyzed in 58 families (46 with reciprocal and 12 with Robertsonian translocations) ascertained for birth of a malformed child, recurrent spontaneous abortion, or hypogonadism. These families include a total of 122 informative sibships. The analysis of the data, after correction for ascertainment bias, showed that the incidence of spontaneous abortion is nearly 50% in reciprocal and between 20 and 25% in Robertsonian translocation families ascertained for malformed child or recurrent abortion. The risk of malformed infants with unbalanced genome is approximately 6% among the liveborn offspring of reciprocal translocation carriers and 23% among the liveborn offspring of carrier mothers of t(14q21q). The distribution of the breakpoints on the chromosomes involved in reciprocal translocations ascertained through a malformed child is nonrandom, with an excess on chromosomes 5, 9, 13, and 15. The study of chromosome imbalance, expressed as gain or loss of a portion of genetic information relative to the total haploid autosome length (percent HAL), shows that among the common types of disjunction-segregation leading to unbalanced gametes, adjacent 1 seems to be the one producing on the average the least level of genome imbalance. This explains why it is the most frequently observed type of segregation giving rise to gametes from which subjects with a chromosome imbalance compatible with life can be generated.

Abortion, Habitual↗
PubMed1983

Normal and altered otoliths of guinea pigs. Scanning electron microscopy observations.

Normal morphology and structural alterations of the otoliths were observed in 20 young albino guinea pigs. Ten animals had been exposed to long-term treatment with an aminoglycoside antibiotic and ten others, which had not been treated, have been analyzed as a control group. The observations were carried out using scanning electron microscopy. All the animals survived the period of stabling and treatment. They were sacrificed and the temporal bones were dissected and fixed with 2% osmium tetroxide buffered at pH 7.4. The inner ear was subsequently dehydrated, microdissected, dried with CO2, and coated with gold. Different kinds of deterioration were observed and valued according to the appearance of the otoliths, which looked as if they had been melted, with many pores and wide and prominent cavitations probably due to chemical etching.

Animals↗
PubMed1983

Two new estrogen-supersensitive variants of the MCF-7 human breast cancer cell line.

Two new estrogen-sensitive variants of MCF-7 human breast cancer cells, CG-4 and CG-5, are described in this report. These cells were derived from a casual contamination by MCF-7 cells of primary cultures from a human adenocarcinoma of the breast and a pleural effusion of a patient with advanced breast cancer, respectively. Careful characterization of these variants revealed chromosomal properties highly similar to and alloenzyme phenotypes identical to those of MCF-7 cells which were simultaneously cultured in the laboratory. MCF-7, CG-4 and CG-5 cells were tested for estrogen responsiveness under identical growth conditions, that is in the presence of culture medium supplemented with 5% charcoal-treated serum. While the number of MCF-7 cells increases by about 40% over the controls in the presence of physiological concentrations of estradiol, the number of CG-4 cells doubles and the number of CG-5 cells triples. All these cell lines have approximately the same number of estrogen, androgen, glucocorticoid, and progesterone receptor sites/cell. Since several difficulties arise in demonstrating the estrogen responsive growth stimulation of currently available human breast cancer cells, these two new variants, characterized by a high and reproducible estrogen responsiveness, afford a new model for studying the mechanisms by which estrogen regulates cell proliferation. The problems related to the careful characterization of every established cell line are discussed.

Adenocarcinoma↗