Increase in triglycerides during alpha-interferon treatment of chronic viral hepatitis.
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Adolescent↗
Biomedical subjects
M Santos
Publications and source records attributed to M Santos.
On the use of tester stocks to predict the competitive ability of genotypes.
It has been recently claimed that the outcome of competition between two phenotypically indistinguishable strains cannot be predicted from comparisons of their respective performances against a mutant tester stock. Our aim in the present paper is to disprove this claim and to show the potential pitfalls of deriving conclusions from a statistical analysis of experimental designs commonly employed for the study of competitive interactions in genetically homogeneous and heterogeneous mixtures. Using our own data, we conclude that evaluating the competitive interactions of phenotypically indistinguishable wild-type strains by competing them against mutant marked stocks still remains a valuable method.
Analysis of Variance↗
The evolutionary history of Drosophila buzzatii. XXV. Random mating in nature.
Using allozymes as the genetic probe, data are presented which show that wild Drosophila buzzatii females and males engaged in copulation mate at random. Hence, putative inbreeding due to local mating of genetically related flies emerging from the patchy distributed substrates, was not detected. We conclude that individuals raised from a niche disperse and mate at random with other members of the population, so only one round of drift due to the colonization of suitable and ephemeral breeding sites is taking place.
Alleles↗
Factors affecting in vitro growth of harvested enterocytes.
Selective enterocyte transplantation may be an alternative to whole organ transplantation for increasing absorptive capacity. Our aim was to determine the effect of initial cell number and viability, proportion of intact crypts, and basement membrane components (BMC) on the in vitro growth of rabbit enterocytes. Enterocytes were harvested using warm trypsinization from ileal segments in 40 rabbits. Initial cell viability was 92 +/- 4% (mean +/- SD), cell yield was 7.7 +/- 3.6 x 10(6) cells/cm, and there were 0.51 +/- 0.33 crypts/100 cells. Initial cell viability correlated with cell yield (r = -0.508, p < 0.001) and % crypts (r = 0.313, p < 0.05). Cell yield also correlated with % crypts (r = -0.645, p < 0.001). Enterocytes (5 x 10(6)) were incubated in growth media in plain or BMC coated growth culture vessels for 14 days. There was a correlation between both number of cells seeded (r = 0.824, p < 0.001) and cell viability (r = -0.696, p < 0.01) and % growth colonies containing epithelial cells at 14 days. Both total growth colonies (r = -0.565, p < 0.05) and colonies with epithelial cells (r = -0.589, p < 0.05) had a negative correlation with % crypts. Incubating cells in BMC coated vessels (n = 6) resulted in significantly more dispase liberated cells after 14 days than in plain vessels (n = 6) (6.6 +/- 1.1 vs. 3.8 +/- 1.0 x 10(6), p < 0.05) but viability was similar (97 +/- 2% vs. 96 +/- 2%).(ABSTRACT TRUNCATED AT 250 WORDS)
Amine Oxidase (Copper-Containing)↗
A multiparametric study of malignant lymphoma of mucosa associated lymphoid tissue (MALT).
A morphological, immunophenotypic and ultrastructural study, cell cycle estimation, DNA and cytogenetic analysis were performed in ten cases of B-MALT lymphomas. Five had low grade lymphoma and five had high grade. Low and high grade cases showed the same cells but in different percentages: These included centrocyte-like cells with occasional monocytoid cytoplasmic changes, and centroblast-like cells. However, in high grade cases more dysplastic and large cells were present. All cellular types showed an important development of rough endoplasmic reticulum. In all cases a large panel of monoclonal antibodies was employed to study the B-cell immunophenotype. Ki-67 positivity ranged from 5% to 30% in low-grade cases and from 50% to 70% in high-grade cases. Gene rearrangement analysis showed rearrangement with Jh probe and half of the cases were also rearranged with the Kde probe (Kappa constant chain gene). A rearrangement banding pattern with TCR genes was not present in any of the cases. Cytogenetic study showed complex alterations in high grade cases and a normal karyotype in low grade lymphomas. Only one case had rearrangement for the bcl-2 probe.
Female↗
[Castleman's disease. A multifactorial study].
A case of Castleman's disease (hialino-vascular subtype) in a female patient 15-years-old is considered. Clinically there were isolated lymphadenopathies which relapsed after surgery and absence of general syndrome. Histoimmunological and electron microscopic studies were performed as DNA rearrangement and cytogenetics in order to exclude genetic abnormalities and monoclonality of this disorder. The role of follicular dendritic component in discussed.
Adolescent↗
Magnetorotons in quasi-three-dimensional electron systems.
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Journal Article↗
Candida albicans and three other Candida species contain an elongation factor structurally and functionally analogous to elongation factor 3.
A cell-free poly(U)-dependent translation elongation system from Candida albicans is ATP-dependent due to the presence of an elongation factor 3 (EF3)-like activity. Saccharomyces cerevisiae ribosomes added to a C. albicans postribosomal supernatant (PRS) supported poly(U)-dependent elongation, suggesting that the C. albicans lysate contained a soluble translation factor functionally analogous to the S. cerevisiae translation factor EF-3. The presence of EF-3 in C. albicans was confirmed by Western blotting using an antibody raised against S. cerevisiae EF-3. This antibody was also used to screen a selection of Candida species, all of which possessed EF-3 with molecular mass in the range of 110-130 kDa.
Candida albicans↗
Intraoperative radiotherapy in the multidisciplinary treatment of bone sarcomas in children and adolescents.
From September 1984 to December 1989, 38 patients of pediatric age with localized bone sarcomas received intraoperative radiotherapy (IORT) as part of a multidisciplinary treatment program. The age ranged from 6 to 21 years. The tumor histologies were 22 osteosarcomas and 16 Ewing's sarcomas. Thirty-four had initial primary disease (90%) and 4 were treated for local recurrence (10%). IORT was used on 32 untreated patients and in 6 previously treated with external beam radiotherapy (EBR). The IORT field included the surgically exposed tumor bed area. Single radiation doses ranging from 10 to 20 Gy were delivered, using 6-20 MeV electron beams. The median follow-up time for the entire group is 25 months (2-65+ months). The projected 5-year disease-free and overall survival rates are 65% and 69%, respectively. One patient developed a local recurrence in each histological group: one chondroblastic osteosarcoma and one cervical Ewing's sarcoma. Six patients died from metastatic progression: 3 initially recurrent tumors and three primary disease cases. Severe neuropathy and soft tissue necrosis were seen in some patients as IORT related complications. IORT is a feasible technique to be integrated in multidisciplinary programs that may promote local control in pediatric and adolescent patients with bone sarcomas. Peripheral nerves are dose-limiting tissue structures for IORT.
Adolescent↗
Characterization of topoisomerase I and II activities in nuclear extracts during callogenesis in immature embryos of Zea mays.
We have characterized the topoisomerase I and II activities in nuclear extracts from immature embryos of Zea mays and the effect of the treatment with 2,4-dichlorophenoxyacetic acid (2,4-D) and abscisic acid (ABA). These extracts were shown to be essentially devoid of protease and nuclease activities and they were tested for their ability to relax supercoiled DNA, unknotting P4 DNA and catenate circular duplex DNA under catalytic conditions. Unknotting and catenation reactions are strictly magnesium- and ATP-dependent, but not the relaxation of circular supercoiled DNA allowing the detection of both topoisomerase I and II activities. Two cytotoxic drugs, camptothecin, a plant alkaloid that inhibits eukaryotic topoisomerase I, and epipodophyllotoxin VM-26 (teniposide) that inhibits topoisomerase II, have been assayed in our extracts showing similar inhibitory effects on topoisomerase enzymes. Alkaline phosphatase treatment of nuclear extracts abolishes both topoisomerase activities. Nuclear extracts from embryos treated with 2,4-D showed 200% increase on topoisomerase II activity as compared with untreated ones, but only residual activity was detected in ABA-treated embryos. Nuclear extracts from hormone-treated and untreated embryos showed similar topoisomerase I activity with deviations of less than 25%. These differences are discussed in terms of possible post-translational modifications of the enzymes associated with the increase in proliferation activity of calli.
2,4-Dichlorophenoxyacetic Acid↗
Effect of trypsin and 2-mercaptoethanol on the exposure of sugar residues on the surface of Leishmania donovani chagasi.
Using transmission electron microscopy, gold-labeled lectins, morphometry and enzyme-linked lectin assay, we could show that treatment of promastigotes of Leishmania donovani chagasi with trypsin did not interfere with the binding of lectins (concanavalin A, peanut agglutinin, wheat germ agglutinin and Ricinus communis agglutinin) to the parasite surface. These observations are in agreement with results we previously obtained using a biochemical approach. Treatment of fixed promastigotes with 2-mercaptoethanol induced a significant increase in the density of concanavalin A (Con A) receptors on the surface of L. d. chagasi in relation to the control. We suggest that this increase is due to the unfolding of one or more surface glycoproteins after cleavage of disulfide bonds between cystein residues in adjacent protein loops, exposing second-order Con A receptors that are otherwise hidden in the protein quaternary structure.
Animals↗
An epidemiological study of malaria in Bioko and Annobón islands (Equatorial Guinea).
A seroparasitological study of malaria was carried out in two of the more important islands of Equatorial Guinea, Bioko (ex Fernando Poo) and Annobón. The study involved a randomly-chosen population of children aged from two to nine years. In Bioko 1130 children were chosen from 29 of the 51 villages on the island; in Annobón 185 children were chosen from the capital town, where all the population lived. Indirect immunofluorescence tests (IFAT) showed a prevalence of malaria infection of 29.8% in Bioko and 55.7% in Annobón. The parasitic prevalence (malaria index) was 26.6% and 55.1% respectively, and the splenic index was 57.0% and 54.6% respectively. The results indicate that this is an area of stable hyperendemic malaria, which may benefit from an antimalarial programme.
Age Factors↗
Evaluation of diagnostic methods for Helicobacter pylori gastritis.
The authors evaluated the use of direct Gram-stained smears, 1- and 24-hour urease broth tests, histologic examination, and culture to detect Helicobacter pylori in 100 gastric biopsy specimens from 97 patients with epigastric symptoms. Twenty-six patients had positive cultures and 27 had H. pylori identifiable in hematoxylin and eosin-stained sections. The gastric biopsy specimens from the 29 patients with culture and/or histologic findings positive for H. pylori showed active gastritis in 27 cases (93%), compared with 26 cases (37%) without H. pylori (P less than 0.0001). Chronic gastritis was present in 25 cases (86%) with H. pylori and 40 cases (56%) without H. pylori (P less than 0.01). Twenty patients had positive Gram-stained smears. Fifteen patients had positive 1-hour urease tests, and 3 had delayed positive 24-hour urease tests. There were no false-positive Gram's stain results, three false-positive 24-hour urease tests, two false-negative histologic results, and three false-negative cultures (one inadvertently incubated anaerobically). The sensitivities of the methods were as follows: 62% for the 24-hour urease test, 69% for direct Gram's stain, 90% for culture, and 93% for histologic examination. The authors conclude that the urease test used in this study has low sensitivity and limited specificity; that the direct Gram-stained smear is a useful, highly specific, rapid screening test; and that the lengthier methods of culture and histologic examination have comparably high sensitivity for the definitive diagnosis of H. pylori gastritis.
Bacteriological Techniques↗
Genetic variance for body size in a natural population of Drosophila buzzatii.
Previous work has shown thorax length to be under directional selection in the Drosophila buzzatii population of Carboneras. In order to predict the genetic consequences of natural selection, genetic variation for this trait was investigated in two ways. First, narrow sense heritability was estimated in the laboratory F2 generation of a sample of wild flies by means of the offspring-parent regression. A relatively high value, 0.59, was obtained. Because the phenotypic variance of wild flies was 7-9 times that of the flies raised in the laboratory, "natural" heritability may be estimated as one-seventh to one-ninth that value. Second, the contribution of the second and fourth chromosomes, which are polymorphic for paracentric inversions, to the genetic variance of thorax length was estimated in the field and in the laboratory. This was done with the assistance of a simple genetic model which shows that the variance among chromosome arrangements and the variance among karyotypes provide minimum estimates of the chromosome's contribution to the additive and genetic variances of the trait, respectively. In males raised under optimal conditions in the laboratory, the variance among second-chromosome karyotypes accounted for 11.43% of the total phenotypic variance and most of this variance was additive; by contrast, the contribution of the fourth chromosome was nonsignificant. The variance among second-chromosome karyotypes accounted for 1.56-1.78% of the total phenotypic variance in wild males and was nonsignificant in wild females. The variance among fourth chromosome karyotypes accounted for 0.14-3.48% of the total phenotypic variance in wild flies. At both chromosomes, the proportion of additive variance was higher in mating flies than in nonmating flies.
Animals↗
Factors affecting distribution of alveolar surfactant during resting ventilation.
Few studies have been done to establish the ventilatory factors affecting alveolar surfactant under resting conditions. Experiments in which ventilatory variables were recorded for 4 h were performed in 12 adult cats breathing spontaneously under pentobarbital sodium anesthesia. After the animals were killed and bronchoalveolar lavages (BALs) were performed, the resulting fluid was subjected to differential centrifugation and determinations of proteins, phospholipids (PL), and disaturated phosphatidylcholine (DSPC). Pellet P1+2 was obtained by two centrifugations at 140 g; the supernatant was centrifuged at 1,000 g to obtain pellet P3 and subsequently at 60,000 g to obtain P4. Pellets P3 and P4 had the higher contents of PL and DSPC. Bivariate and multivariate correlational analyses indicate that 1) total PL in BAL was not related to any of the ventilatory variables studied, 2) PL in P3 and P4 fractions was directly correlated to the physiological range of variations in the frequency of large spontaneous gasps (fL), and 3) PL in P1+2 fraction was inversely related to fL. Cats subjected to bilateral section of carotid nerves, although presenting reduced chemosensory drive and ventilatory chemoreflexes, did not exhibit significant differences in resting ventilatory variables nor in alveolar surfactant components. Present results indicate that the total content of alveolar surfactant is not modified by ventilatory variations within physiological range but that the spontaneous occurrence of large gasps increases the proportion of more active forms of alveolar surfactant. This may mediate the role of augmented breaths in keeping lung compliance and preventing atelectasis under resting ventilatory conditions.
Animals↗
Intraoperative radiotherapy in gastric and pancreatic carcinoma: a European experience.
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Combined Modality Therapy↗
Intraoperative radiotherapy in thoracic tumors.
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Combined Modality Therapy↗
[Cytogenetic and molecular aspects in MALT lymphomas].
Cytogenetic and molecular results in 10 patients with extranodal lymphoma (MALT): 5 low grade and 5 high grade, were compared with the results observed in nodal lymphomas. This study suggests that there are cytogenetic differences between extranodal and nodal low grade lymphomas. Both molecular analysis by conventional Southern blot with probes for the major and minor regions of bcl-2 gene, and PCR analysis with primers from these regions, showed that t (14; 18) is a sporadic event in MALT lymphomas.
Aneuploidy↗