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Biomedical subjects

C A Redi

Publications and source records attributed to C A Redi.

At least 55 records · Page 3Linked to original sources
PubMed1986

Cytochemical evaluation of sperm and lymphocyte DNA content after treatment with 5 N HCl.

In situ as well as extra situm cytochemical methods were used to investigate why the observed Feulgen-DNA value of sperm versus lymphocyte cells is lower than expected. After treatment with 5 N HCl, in situ experiments involving the GCA reaction and the UV cytophotometry showed the loss of DNA in sperm nuclei to be 12% more than that in lymphocyte nuclei. Extra situm study of sperm and lymphocytes treated with 5 N HCl showed the phosphate and DABA contents of sperm to be 35% and 23%, respectively, less than those of lymphocytes. The data suggest that sperm chromatin is much more sensitive than somatic chromatin to HCl depolymerization during the Feulgen reaction, and this can tentatively be attributed to the protein complement of sperm chromatin.

Animals↗
PubMed1985

The effects of some Robertsonian chromosome combinations on the seminiferous epithelium of the mouse.

In Mammals, structural rearrangements of the karyotype cause considerable trouble to the spermatogenic process. Making use of an experimental animal model of Robertsonian chromosomal variation in the house mouse (Gropp, Winking & Redi, 1982a) the effects of these chromosome structural rearrangements on the spermatogenic process were studied in fertile and chromosomally derived subfertile and sterile mice. Each karyotype condition was related to the cytological composition of the twelve stages of the seminiferous epithelium, studied in PAS-haematoxylin-stained testicular sections, with the following results: in subfertile males there is a depletion of spermatogonia in the regenerating compartment but their differentiation is not affected. In the sterile males there is degeneration of primary and secondary spermatocytes and massive spermatid degeneration. Spermatocyte development is retarded in nearly 50% of the spermatocyte population in subfertile males. Moreover the ratio between primary spermatocytes and spermatids is reduced to about 1:2 in subfertile males, while the few spermatids produced in sterile males had degenerated during stages I to VIII. The number of Sertoli cells/100 micron throughout the cycle of spermatogenesis is the same in the three conditions studied. These data indicate that the spermatogenic process is affected by structural changes not only at the meiotic level (primary spermatocyte failure to follow the normal pattern of differentiation and occurrence of defective spermatids) but also at the premeiotic stage, when undifferentiated spermatogonia are regenerating.

Animals↗
PubMed1984

Influence of the C-banding procedure on DNA and proteins of mouse chromosomes: I. A microdensitometric study.

Cytochemical quantitative methods were used to investigate DNA protein contents of mouse metaphase plates during an alkaline C-banding procedure ( Sumner et al., 1971). Cytochemical stains and reactions for DNA and for total protein content were used to quantitatively assess the sequential involvement (losses) of DNA and protein during the appearance of the classic C-banding pattern which was monitored with Giemsa staining. The data point the preferential loss of DNA from euchromatic regions of chromosomes as the main cause of the C-banding pattern appearance. The effect of chromosomal protein is more likely indirect and perhaps tied to some specific interaction with centromeric DNA that contributes to DNA retention in C-bands. Following the C-banding procedure it was possible to differentially stain the centromeric area with Feulgen and GCA and even with non-fully specific stain for DNA such as methylene blue.

Animals↗
PubMed1984

Infantile-acute acid maltase deficiency (Pompe's disease): studies of muscle cultures.

Muscle was cultured from a 7-month-old boy affected by generalized weakness, macroglossia, cardiomegaly, hepatomegaly and increasing dyspnea. Muscle biopsy showed a vacuolar myopathy with glycogen accumulation (Pompe's disease). The muscle was cultured to verify whether the abnormality could be expressed in culture during myogenesis. In the living muscle cultures, phase-contrast microscopy revealed that myotubes as young as two weeks were vacuolated and that the vacuolization was higher in the older cultures compared to parallel control cultures. Fluorescent microscopy by acridine orange staining of the cultures showed a marked increase in acridine orange positive material (presumptive lysosomes) throughout the sarcoplasm. Electron microscopic data revealed myofibrillar destruction in the muscle biopsy and vacuolized cytoplasm in the Schwann cells. Cytochemically, the patient's myotubes stained very intensely for acid phosphatases. The increased acid phosphatase activity was quantitatively confirmed by cytophotometric evaluation performed on patient and control parallel myotubes. This is the first evidence that an increase in acid phosphatases has been quantitatively demonstrated in cultured muscle from a patient with acute infantile onset acid maltase deficiency (Pompe's disease) although the enzymatic activity was assayed at only one time of incubation.

Cells, Cultured↗
PubMed1983

Nuclear DNA content distribution in five parotid gland tumors. A preliminary report.

Quantitative cytophotometric evaluations of nuclear DNA content were made on epithelial cells obtained from five cases of parotid gland tumors. The measurements were performed on sections stained with Feulgen reaction and, as control of diploid value, adventitious small lymphocytes as well as normal epithelial cells were considered. A fairly good correlation between the type of histogram of DNA values and a progressive degree of atypia was found since particularly high levels of hyperdiploidy were found in more severe tumors.

Adult↗
PubMed1982

Cytochemical assessment of chromatin characteristics during sperm cytodifferentiation in mouse.

Cytochemical quantitative reactions either for DNA or proteins were performed on spermatozoa in the last stages of the sperm cytodifferentiative process. The analysis of the discrepancy between the expected (1C amount) and the evaluated reaction intensities sheds light on the chromatin condensation phenomenon. The high inactivation and protection of the paternal genome in a particularly packed chromatin has generally been regarded as the cause of non-stoichiometric responses by DNA specific reactions. We suggest that this interpretation fits well for specific DNA reactions based on intercalation between base pairs or DNA phosphate groups binding, but for the Feulgen reaction the cause is more complex and pertains to the particular susceptibility of the sperm chromatin to depolymerization by hydrolysis in the Feulgen reaction.

Animals↗
PubMed1981

Analysis of some cytotopochemical parameters for a definition of the chromatin status.

A study of the curves of Feulgen hydrolysis kinetics has been performed on different cell types of the same animal species and on the same cell type from different species at different taxonomical level. The curves were analyzed by a computer programme of least square fit to the Bateman's function, which gives a description of DNA hydrolysis kinetics by three parameters only: 1) amount potentially stainable groups; 2) depurination rate constant; 3) depolymerization rate constant. The chromatin homogeneity within the nucleus seems to affect these parameters, together with the degree of chromatin compaction. Furthermore the thermal denaturation (100 degrees C), also after fractionate histone extraction, shows a resistant DNA fraction, which does not appear to be affected by the degree of chromatin compaction only.

Animals↗
PubMed1980

Quantitative aspects of the cytochemical Feulgen-DNA procedure studied on model systems and cell nuclei.

Quantitative aspects of DNA losses during fixation and pararosaniline(SO2)-Feulgen staining of microscopic preparations were studied. The preparation of a new cytochemical model, consisting of DNA-protein layers (with thicknesses between 0.1 and 5.0 micrometer) on microscopic glass slides is described and potentialities and limitations of this model are discussed. Polyacrylamide films into which high molecular weight calf thymus DNA or chicken erythrocyte nuclei had been constrained served as another model. As biological objects chicken erythrocyte nuclei and rat liver nuclei either in suspension or on microscopical glass slides were used. The experimental results indicate a loss of about 5% of the DNA due to the fixation procedure applied. Hydrolysis in 5 N HCl at room temperature, staining with the pararosaniline-Schiff medium and rinsing with sulfurous acid induced losses of DNA too, varying in amount depending on the type of preparation used. About 10% of the original DNA content is lost in total from chicken erythrocyte nuclei and rat liver nuclei dried on microscopical glass slides, from chicken erythrocyte nuclei constrained in polyacrylamide films, and from DNA-protein layers on microscopic glass slides. For nuclei fixed and stained in suspension the total losses amount to about 40%. The differences in losses between various types of preparations are discussed. Biochemically, the content of DNA originally present per chicken erythrocyte nucleus was determined to be 2.52 pg, a value, which is in good accordance with reliable biochemical data published already. It is shown that calibration of cytochemical staining intensities into biochemical units or absolute amounts of material by use of a model system, is only reliable when it is known or to be expected that both the loss of material due to fixation and staining, and the stoichiometric relation between material present and dye molecules is identical. The same holds for the application of internal biological reference systems.

Animals↗
PubMed1980

On chromatin availability to hydrolysis of the Feulgen reaction in Purkinje neuron population: microdensitometric and microfluorometric data.

The earlier finding that the chromatin organization of Purkinje neurons is not the same in the whole population is confirmed in this study. This was found to be independent of the type of Feulgen reaction hydrolysis kinetics, analytical method (microdensitometry or microfluorometry) and tissue preparation (sections, isolated cells, isolated nuclei). This heterogeneity, possibly linked to different functional stages, leads to Feulgen-DNA contents which, at optimal hydrolysis times, range from 2c to 4c values. The results obtained are discussed in relation to those in the literature.

Animals↗
PubMed1979

Feulgen-DNA content of the Purkinje neuron: "diploid" or "tetraploid"?

Microdensitometric measurements of the Feulgen-DNA content of the Purkinje cells and of the small granular cells (2c control) were carried out at lambda 550 nm and by the two wavelength method according to Fukuda et al., and were also corrected for the glare. We analysed sections of perfused cerebella and isolated cells of cerebellar cortex from adult rats. The Purkinje cells had a mean value of Feulgen-DNA content 30-45% higher than the 2c value, irrespective of the methods of preparation or measurement.

Animals↗
PubMed1976

[Quantitative limits of the Feulgen reaction: analysis of interference caused by dehistonization and denaturation and renaturation treatments].

The Feulgen reaction intensity (measured with a microdensitometer Vickers M86 on the nucleus of erytrocytes of Xenopus laevis Daud.) is increased after dehistonization according to Brody (1974) only if the dehistonization is made before the fixation in acetic acid. The denaturation and renaturation treatments which should act specifically on the screws of the DNA and therefore should not affect the Feulgen reaction, act in a specific manner, probably going away another histonic components. On the dehistonized material the action of the hydrolysis of the Feulgen reaction would add up to that implicit in the dehistonization treatment and would cause a rapid fall of the values for loss of material as consequence of depolymerization facts, according to Andersson and Kjellstrand (1975). The successive renaturation treatment both on dehistonized and on non dehistonized material does not change significantly the values precedently obtained and this confirms the idea that the rilevability of the Feulgen reaction is not influenced by the treatments "per se" but by the deep "touching" of the chromatin components.

Animals↗
PubMed1976

[Some cytochemical characteristics of the chromatin in the erythrocytes of Xenopus laevis Daud].

The Xenopus laevis Daud. genome offers a stimulating model of a chromatin (Davidson et al., 1975) in which a high ratio of repetitious DNA sequences has been recorded (45% of total genome according to Davidson et al., 1975). We have studied cytochemically this model "in situ", on the erythrocytes of air-dried smears of peripheral blood. The cells, which are non-dividing and not engaged in DNA reduplication, constitute almost hypothetically a homogeneous class constantly in G1 phase of the cellular cycle. Our methods are: a) analysis on the curves of Feulgen hydrolysis kinetics to attempt to find the depurination and depolymerisation patterns of DNA according to Andersson et al. (1975); b) determination of the DNA resistence ratio to chemical denaturation with a quantitative relative microdensitometric determination of methyl-green staining, according to Scott (1967) specific technical conditions. For comparison, qualitative and preliminarly subjective control determinations have been made with acridine-orange in correspondent denaturation conditions. Both the a) and b) methods have been performed with and without previous HCl dehystonisation and with and without formaldehyde pretreatment. The results with the a) and b) methods have not yet been theoretically compared and the possibility of an approach to this correlation is discussed here as a tool for a possible cytochemical quantitative measure of the nuclear fraction of repetitious DNA "in situ".

Animals↗