Changes in elemental concentrations in K562 target cells after conjugation with human lymphocytes studied by X-ray microanalysis.
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Cells, Cultured↗
Biomedical subjects
A Campos
Publications and source records attributed to A Campos.
Sister chromatid differentiation after in situ detection of ultraviolet-induced DNA breaks under electron microscopy.
Chinese hamster DON cells with 5-bromodeoxyuridine (BrdU)-substituted chromosomes were ultraviolet (UV)-exposed and processed for in situ detection of induced DNA breaks under electron microscopy. For this purpose, UV-induced breaks were amplified by an exonuclease III digestion to obtain single stranded DNA motifs which could hybridize with oligonucleotides of random sequences. These reannealed motifs could be used as primers which were extended by the Klenow polymerase, incorporating biotinylated-dUTP that was detected by a gold-tagged streptavidin. After processing, the chromatid whose DNA was BrdU-substituted in one strand showed a higher electron density than the chromatid substituted in both strands. In contrast, the unifilarly substituted chromatid showed about twice the labelling of DNA breaks as the bifilarly substituted one. This result could be the consequence of a greater loss of chromatin tracts in the bifilarly substituted chromatid, as implied by an X-ray microanalysis which showed that the amount of phosphorous lost by the bifilarly substituted chromatid was higher than that of the unifilarly substituted chromatid.
Animals↗
Assessment of Yqh translocations.
Two initially presumed Yqh translocations, one to Xp and another to 21p, were assessed by conventional banding procedures, 5-azacytidine treatment, electron microscopy, and fluorescence in situ hybridisation. While the Yqh nature of the heterochromatic block from Xp was confirmed, this was not the case with the 21ph+ variant. In conclusion, conventional banding techniques are insufficient to diagnose Y;G translocations.
Azacitidine↗
An extra band within the human 9qh+ region that behaves like the surrounding constitutive heterochromatin.
An extra variant G band in a human 9qh+ region was analysed in normally condensed and 5-azacytidine undercondensed chromosomes. Fluorescence in situ hybridisation showed that specific, classical, alphoid and beta satellite DNA was not present. Nevertheless, this extra band behaves like the surrounding heterochromatin because (1) its chromatin fibres showed condensation inhibition after 5-azacytidine treatment, as confirmed by electron microscopy, and (2) it was not affected by in situ digestion with the restriction endonucleases AluI and Sau3A. These results suggest that this variant band may correspond to euchromatin that has become inactivated by a position effect.
5-Methylcytosine↗
Influence of creativity on vividness of imagery.
We studied the correlations between creativity and imagery in 1361 university students of Fine Arts, Mathematics, and Geography and History. Significant values were found between certain factors of creativity and imagery, but creativity only accounted for 6% of the total variance in vividness of imagery for the whole sample.
Adolescent↗
Gentamicin ototoxicity in otoconia: quantitative electron probe X-ray microanalysis.
Chronic gentamicin ototoxicity was evaluated in the otolithic membrane of adult OF1 mice at the otoconial layer of the saccule and utricle by quantitative electron probe X-ray microanalysis of Ca and K. The otolithic membranes were plunge-frozen and freeze-dried. The analysis was carried out with an energy dispersive detector using the peak-to-back-ground ratio method and different inorganic salts of Ca and K as standards to calibrate the microprobe. Ca and K in the otoconia are related via a linear function in both the saccule and the utricle. This association is not maintained after exposure to gentamicin, which suggests that this aminoglycoside antibiotic interferes with the Ca-K equilibrium in the otoconia. A dose of 200 mg/kg gentamicin twice a day for 5 days did not affect Ca in the mineral phase of the otoconia, but did increase K in both saccular (p < 0.05) and utricular (p < 0.01) otoconia. These increases in K may reflect a modification in the composition of the endolymph, resulting from cellular damage at the plasma membrane.
Animals↗
Standards for X-ray microanalysis of calcified structures.
The ability of electron probe X-ray microanalysis (EPMA) to solve biological problems often depends on the use of a quantitative approach. EPMA allows the quantitative determination of chemical elements of biological materials by using reference standards which resemble the specimen in the mode of interaction with the electron beam. Although there is a large experience in the quantification of elements in biological thin specimens, experience with standards for X-ray microanalysis of bulk specimens is limited, especially for calcified structures where the density of the specimen is difficult to estimate. The quality of the results in EPMA depends on obtaining accurate calibration curves which allow the establishment of the relationship between the signal measured and the concentration of the element of interest. The different methods for specimen preparation and the thickness of the specimen will also determine the precise nature of the standardization technique to be adopted. The physics of the electron beam-specimen interactions impose limitations upon the accuracy of calibration, and the choice of an unstable standard can result in large errors in the quantification of elements. We have reviewed the different types of compounds that have been used as standards for biological EPMA of thin and bulk specimens and discuss their potential use for quantitative analysis of mineralized tissues, with special reference to otoconia, the calcified structures of the vestibular system.
Animals↗
Pseudoisodicentric nature of a normal length non-fluorescent Y chromosome.
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Adolescent↗
Regional differences in cell surface patterns in normal human sulcular epithelium.
Studies with scanning electron microscopy in the normal human sulcular epithelium are scarce, and no precise information exists about cell surface patterns along the epithelium, the frequencies of these patterns, or possible regional differences within the mouth. In five periodontal biopsy specimens each from the anterior and posterior region of the mouth, we observed three cell patterns on the basis of the overall appearance of morphological surface markers in the coronal and apical zones of sulcular epithelium: microvilli; microplicae; and pits. The percentage of keratinocytes showing the microvillous pattern in the surface of apical sulcular epithelium of the posterior region of the mouth was significantly higher than in the anterior region. We posit that the presence, in the bottom of the normal sulcular epithelium in the posterior region of the mouth, of mainly microvillous keratinocytes (the most undifferentiated and least desquamative type of keratinocyte, and thus the most vulnerable to bacterial colonization) can be associated with observations of longitudinal clinical studies of periodontal disease, which suggest that more severe clinical findings are found in the region of the molars.
Adult↗
Frequency of sister chromatid exchanges in humans at 14-16 week foetal stage and at birth.
In order to identify transplacental induced mutagenicity in humans the baseline frequency of sister chromatid exchanges (SCEs) in amniotic fluid cells (8.56 +/- 0.28 per cell) from 14 to 16-week-old foetuses as well as in peripheral blood lymphocytes (7.96 +/- 0.26 per cell) from newborns was determined. A group of twelve patients who were analysed both at 14-16 weeks gestation and at birth showed no SCE variations. These results suggest that foetal amniocytes and T lymphocytes from newborns present a similar sensitivity to the mutagenic activity of the thymidine analogue 5-bromodeoxyuridine employed in the sister chromatid differentiation.
Adult↗
[Evaluation of 4 media for the isolation of Helicobacter pylori from gastric biopsies].
BACKGROUND: Different culture mediums were used for the isolation of Helicobacter pylori. In this study three mediums commonly used for the culture of this microorganism were evaluated: chocolate agar, Martin-Lewis medium and CP of Dent medium as well as a new selective medium Pylori agar. METHODS AND RESULTS: Over a period of 7 months gastric biopsies were collected in 112 patients with clinical manifestations of chronic atrophic gastritis. H. pylori was isolated in some of these mediums on 73 occasions (65.1%). On 72 of the 73 occasions the microorganism grew in the Pylori agar medium (98.6%) being the medium achieving the greatest number of isolations, followed by the CP of Dent medium with 67 isolations (91.7%), 65 isolations with the Martin-Lewis medium (89.0%) and 57 isolations with chocolate agar (78.0%). The chocolate agar medium was that which most frequently presented contaminant flora (35 times: 61.4%) and the CP of Dent medium achieved the most rapid and widespread growth. The colonies were largest and therefore easier to recognize in the CP of Dent and Pylori agar mediums. CONCLUSIONS: The authors recommend the association of the CP of Dent and Pylori agar mediums in the isolation of Helicobacter pylori since these two mediums provide the greatest number of isolations with the greatest growth and ease for colony recognition.
Adult↗
A lipid-anchored heparan sulfate proteoglycan is present in the surface of differentiated skeletal muscle cells. Isolation and biochemical characterization.
We have investigated the presence of hydrophobic membrane-associated heparan sulfate proteoglycans (HSPG) on the cell surface of differentiated skeletal muscle cells. A HSPG releasable by incubation with a phosphatidylinositol-specific phospholipase c (PtdIns-PLC) was obtained. HSPG were also isolated from Triton X-100 extracts of the cells. The hydrodynamic characteristics of the PtdIns-PLC-releasable and detergent-extracted HSPG were indistinguishable. SDS/PAGE analysis of the PtdIns-PLC-releasable HSPG indicated a molecular mass of 250 kDa. Analysis of proteins immunoprecipitated by specific antibodies against a HSPG isolated from Schwann cells demonstrated that the antisera precipitated an intact HSPG that was present in the pool of proteins released by PtdIns-PLC and by Triton X-100 from [35S]sulfate labeled cells. Nitrous acid degradation of the immunoprecipitated proteins released by PtdIns-PLC from [35S]methionine labeled cells produced a single 67-kDa core protein. Analysis of hydrophobicity of the purified HSPG revealed that only the HSPG obtained from the detergent extract were able to be incorporated into the liposomes whereas the PtdIns-PLC-released HSPG was not. Immunocytolocalization analysis of the differentiated cells indicated that the PtdIns-PLC-releasable HSPG was located on the cell surface. Prior incubation of the cells with PtdIns-PLC significantly reduced the surface staining. Analysis of skeletal-muscle sections of adult rat skeletal muscles indicated that this HSPG localized exclusively at the endomysium. This localization suggest that these HSPG may be acting as a cell receptor for extracellular-matrix (ECM) components.
Animals↗
Electron microprobe analysis in periodontal guided tissue regeneration.
Electron microprobe analysis was used to determine the evolution of Ca, P and S in regenerated tissue surrounding incisors roots after periodontal treatment with guided tissue regeneration. Our results, which showed increased Ca and P, and decreased S are discussed in relation to the process of mineralization electron probe microanalysis with potentially provided an accurate means of assessing the degree of mineralization in extremely small tissue samples.
Calcium↗
Morphometrical evaluation of triflusal in brain infarction.
MCA occlusion in animals is a common model for experimental stroke. In previous studies we have shown that one of the factors, which influence evolution of an infarct is microthrombosis in the area of infarction and in the surrounding brain tissue. The present study was undertaken for assessment of the number of microthrombi and of the size of brain infarcting in rats treated with the antiaggregatory substance Triflusal. 7 groups of Sprague-Dawley rats, each group consisting of 6 animals, underwent transsphenoidal MCA occlusion. The animals received Triflusal in various amounts from day 2 till day 6. At day 7 animals were decapitated and the brains were fixed in formaldehyde. The brain was dissected at the level of the optic chiasm and embedded in paraffin. Fresh microthrombi were detected py PTAH (Phosphotungstic acid hematoxylin) staining. In each animal the hemisphere with the ischemic lesion as well as the contralateral hemisphere were examined. The area of both hemispheres was calculated by subtraction of the ventricle area from the total brain area of a section. Infarct was defined as the region of necrosis which was sharply demarcated from normal brain. The infarcted area was planimetrically measured to obtain a ratio of infarcted to normal brain. A correlation between the effect of Triflusal, number of microthrombi and size of the infarcted area could be demonstrated. The pathogenetic role of the microthrombi in the evolution of cerebral infarction as well as the effect of Triflusal in different dosages on the number of microthrombi could be clearly assessed by quantitative morphometry.
Animals↗
Early presentation of tuberous sclerosis as bilateral renal cysts.
We report on an infant in whom bilateral renal cysts were the only initial manifestation of tuberous sclerosis. We review the reported cases of infants with this association and emphasize that tuberous sclerosis can present in infancy as bilateral renal cystic disease. The role of the kidney biopsy in providing the correct diagnosis is discussed.
Female↗
Standards for quantification of elements in the otolithic membrane by electron probe X-ray microanalysis: calibration curves and electron beam sensitivity.
An absolute quantitative standardization technique has been developed to measure Ca and K weight fractions (WF) in the otolithic membrane of the saccule and utricle by scanning electron microscopy and electron probe X-ray analysis using the peak-to-background (P/B) ratio method. Microcrystalline salt standards were used to calibrate Ca and K K alpha P/B or Y = (P/B).Z2/A (Z = atomic number; A = atomic weight) against WF at 10, 15, 20 and 25 kV accelerating voltage. The effect of voltage on the calibration, plotting the coefficient of correlation (r) as a function of voltage, was not dependent on the voltage in the range 10-25 kV for Ca standards. K standards were also independent when P/B was corrected for Z2/A. Background counts in the otoconia (Bo) were obtained at 5, 25, 50, 100, 200 and 500 s and used to test the electron beam sensitivity of saccular and utricular otoconia. Bo was not dependent on the spectra acquisition time, with the exception of Bo under K alpha K peak in the saccule at 10 kV. Ca and K WF were determined at 10, 15, 20 and 25 kV in the saccule and utricle, showing similar values regardless of the voltage used. This method of calibration offers several advantages, such as stability, homogeneity, known composition of the standards, high reproducibility at different voltages even without Z2/A correction and the similarity between the otoconia and crystal standards. We recommend the application of this method for other elements and biomineral systems.
Animals↗
Anatomical and clinical correlation with histological and histometric patterns in cryptorchism.
One feature rarely included in studies on cryptorchism is an adequate correlation between anatomical and clinical data and histological patterns of the testis. The present study correlates anatomical and clinical data from 50 patients (age range 2 months-14 years) using 4 different histological and histometric patterns established previously. Three different patterns of progressively severe histological changes corresponding to increasingly marked dysgenetic alterations in the anatomical and clinical patterns were detected. Less severe changes were correlated with mature anatomical and clinical features, whereas testes showing severe histological-histometric changes were correlated with immature anatomical and clinical features. Non-abdominally located testes with Sertoli cell hyperplasia were not significantly correlated with any of the anatomical and clinical features. The histometric patterns described should facilitate the diagnosis of the stage of testicular development on the basis of anatomical and clinical data.
Adolescent↗
Vividness of imagery and creativity.
We evaluated the extent to which vividness of imagery is correlated with creativity in a sample of 1361 university students from different disciplines and assessed which sensory modalities of vividness of imagery best predicted creativity. Vividness of imagery was generally poorly correlated with creativity and, for all subjects combined, explained only about 2% of total variance in creativity. Promising directions for research are mentioned.
Adolescent↗