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Biomedical subjects

A Caratero

Publications and source records attributed to A Caratero.

At least 19 recordsLinked to original sources
PubMed2002

Life span, cancer and non-cancer diseases in mouse exposed to a continuous very low dose of gamma-irradiation.

PURPOSE: To analyse the life-span and pathologies of mice living under a continuous very low-dose gamma-irradiation. MATERIAL AND METHODS: We exposed 300 C57B1/6J female mice, 3 weeks old, to 10 cGy year(-1) gamma-rays while 300 control mice lived in the same room. Irradiation was delivered continuously by thorium nitrate. We kept all the animals until natural death and performed autopsy. RESULTS: No difference was observed in life-span (mean lifespan +/-SE: 805.2 +/- 9.62 days for controls and 815 +/- 9.57 days for irradiated mice), weight curves or food intake. At autopsy, cancer was present in 40.9% of controls and 37.9% of irradiated mice. They were mainly represented by lymphomas (23.7 and 24.9%) and histiocytic sarcomas (12.6 and 8.7%, respectively, for controls and irradiated mice). Vascular diseases occurred in 24.1% of controls and 23% of irradiated mice. Infections were present at autopsy in 14.1 and 12.3%, respectively, of controls and irradiated animals. No statistical difference was observed at the end of the experiment for cancer or non-cancer diseases between the two groups. CONCLUSION: Continuous 10 cGy year(-1) gamma-irradiation had no adverse effect on malignant or non-malignant diseases in this strain of mouse.

Animals↗
PubMed2001

Influence of continuous, very low-dose gamma-irradiation on the mouse immune system.

PURPOSE: To investigate whether continuous, very low-dose gamma-irradiation (10 cGy/year) modifies immune parameters in mice. MATERIAL AND METHODS: C57BL/6 female mice, 4 weeks old, were irradiated for 24 months and compared with control mice living in the same room. B- and T-cell subsets were evaluated by flow cytometry before and after stimulation with lectins; subclasses of immunoglobulins were determined by ELISA 2, 4, 6, 8, 12, 18 and 24 months after the beginning of the irradiation. RESULTS: No difference was found in the percentage of CD4(+) and CD8(+) cells in the thymus and the spleen, or in the reactivity of T-cells to lectins. While the number of B-cells in the spleen remained unchanged, a significant decrease of IgG1, IgG2b and IgG2a was observed after respectively 12, 18 and 24 months of irradiation. CONCLUSION: The parameters of cellular immunity studied were not affected by this chronic low-dose of irradiation, but this dose rate is probably too low to induce the hormetic effect previously described. Further investigations are necessary to assess whether the decline of immunoglobulin secretion is indicative of a lower rate of infectious diseases or a defect in B-cell function.

Animals↗
PubMed1998

Effect of a continuous gamma irradiation at a very low dose on the life span of mice.

BACKGROUND: There is epidemiological evidence that suggests there are beneficial effects of ionizing radiation at low doses. Some experimental studies confirmed this hormetic effect with doses of about 1 cGy/day, but no data concerning very low dose rates are available. OBJECTIVE: The aim of this study was to determine the life span of mice exposed to very low doses of ionizing radiation. METHODS: Six hundred female C57BL/6 mice, 1 month old, were exposed to chronic gamma irradiation at very low dose rates of 7 or 14 cGy/year. These doses are about 25 or 50 times higher than background, but much lower than the doses of about 1 cGy/day used in previous experiments. Three hundred mice living in the same room were used as controls. RESULTS: The life span, after the beginning of the experiment, determined by the survival time of 50% of each population, is increased in irradiated mice: 549 days in controls, 673 days in both irradiated groups. The differences are significant between the control and the irradiation mice. Differences between mice irradiated with 7 or 14 cGy are not significant. CONCLUSIONS: These results confirm the possibility of a nonharmful effect (hormesis) of ionizing radiation. They demonstrate that the paradigm, which states that low-dose effects can be predicted high-dose effects, cannot be systematically applied in radiation biology in general and gerontology in particular.

Animals↗
PubMed1996

[Alveolar lavage cytological data in lung transplants free of bronchial superinfection. Toulouse Lung Transplantation Group].

Total and differential cells counts from 173 bronchoalveolar lavages (BAL) carried out in 19 lung transplanted recipients have been analysed. The patients were separated into seven groups: (a) those without detectable complications (86 BAL); (b) those with acute rejection (AR) (26 BAL); (c) those with bronchiolitis obliterans (BO) (21 BAL); (d) those with intra-alveolar cytomegalovirus (CMV) but asymptomatic (11 BAL); (e) those with an associated intra-alveolar CMV and AR (7 BAL); (f) those with CMV pneumonia (11 BAL); (g) those with infectious pneumonia excluding CMV (11 BAL). The alveolar cytological data were compared to those from control subjects who were smokers (7 BAL) or non-smokers (8 BAL). Excluding the BO group, the total cell count from the BAL of transplanted patients was significantly higher than in the non-smoking controls and was approaching that of the smoking controls. The lymphocytes count was significantly higher in transplanted patients without complication and in the AR group than in the controls, but there was no significant difference between the two groups. There was a significantly greater eosinophilia at the time of AR than either before or after. Eosinophilia was also higher in grade 3 AR than in grade 1 or 2 AR. These data stress the absence of any correlation between the lymphocyte count in the BAL and the existence of AR. Alternatively, the alveolar eosinophilia observed at the time of AR does not allow the possibility of an infection to be elimitated with certainty.

Adult↗
PubMed1993

Antibodies to bladder-tumor-associated antigens as prognosis probes in the flow-cytometric analysis.

Monoclonal antibodies directed against bladder tumor cells (10D1, 7C12, 6D1, 3C6, G4 and E7) and human leukocyte antigen (HLe1) were tested by flow cytometry on 68 bladder tumors involving 10 grade I, 29 grade II and 29 grade III tumors (WHO classification). According to their evolution stage, these tumors can be subdivided into 17 stage Pa, 34 stage P1, 7 stage P2 and 10 stage P3. Fifteen normal bladder samples were used as a control. Analysis of DNA content revealed a first group of 31 tumors with a unimodal DNA profile. In the second groups of 37 tumors, the DNA profile was bimodal. Cells from grade I tumors were labelled with 10D1 and 6D1 antibodies; all these cells showed a unimodal DNA profile. Grade III tumor cells were labelled with antibodies G4 and E7; most of these cells showed a bimodal DNA profile. The percentage of HLe1-positive cells decreased with the pathological grade and stage of tumor. The composition of infiltrating leukocytes was different in unimodal and bimodal tumors. In conclusion, cells of low-grade tumors can be identified with 10D1 and 6D1 antibodies, and antigens recognized by G4 and E7 antibodies are mostly expressed by aneuploid cells. HLe1 antibody demonstrates the importance of the inflammatory reaction in bladder tumors. Moreover, in flow cytometry, leukocytes within a tumor could be used as internal reference for precise measurement of the DNA content of tumor cells.

Antibodies, Monoclonal↗
PubMed1992

Surfactant analysis during Pneumocystis carinii pneumonia in HIV-infected patients.

Pulmonary surfactant is altered in experimental Pneumocystis carinii pneumonia. Although P carinii is a major causative agent of pneumonia in immunocompromised patients, the pathophysiology of lung injury caused by this organism is poorly understood. Therefore, we studied bronchoalveolar lavage specimens obtained from 19 HIV-infected subjects with PCP compared with specimens from ten healthy control subjects. As iterative BAL was performed, 37 BAL specimens were analyzed for protein and phospholipid. The BAL samples were divided into two groups as follows: 22 BAL samples with the presence of P carinii and 15 BAL samples without P carinii. Compared to control subjects, HIV+ BAL presented a significant increase of PR and a decrease of total PL in both P carinii+ and P carinii- BAL, but in P carinii+ BAL, the fall of PL/PR ratio was significantly more pronounced compared to P carinii- (0.09 +/- 0.02 vs 0.19 +/- 0.04, p less than 0.02). The BAL performed during the recovery of PCP showed an improvement of initial biochemical abnormalities. Surfactant composition was also altered, with a phosphatidylcholine and phosphatidylglycerol drop and a sphingomyelin and lysophosphatidylcholine increase. The presence, even in P carinii- BAL, of less polar compounds of undetermined nature, was revealed. We concluded that in HIV+ patients, abnormalities of pulmonary surfactant were present before PCP, and that the development of PCP enhances these abnormalities. These surfactant alterations may contribute to the saprophyte-pathogen transformation of P carinii, but this hypothesis requires further investigation that is presently in progress.

Adult↗
PubMed1990

Flow cytometry analysis of urothelial cell DNA content according to pathological and clinical data on 100 bladder tumors.

DNA content of 100 bladder tumors (34 grade I, 42 grade II and 24 grade III, WHO classification) were studied by flow cytometry. Ten normal bladder samples were used as control. The 100 bladder tumors could then be separated into two groups. A first group of 60 tumors (60%) had a unimodal distribution with a diploid peak and a DNA index close to 1.0, 32 grade I, 22 grade II and 6 grade III tumors displayed this pattern as did the 10 normal bladders. The second group (40%) had a bimodal distribution with two peaks, the first one (diploid peak) with a DNA index of 1.0, the second (aneuploid peak) with a DNA index greater than 1.0. Two grade I, 20 grade II and 18 grade III tumors belonged to this group. Frequency of the aneuploid peak increased with tumor grade and infiltration progression. Hence 6% of grade I, 48% of grade II and 75% of grade III tumors showed an aneuploid peak as well as 8% of Pa, 46% of P1, 73% of P2 and 87.5% of P3 stage tumors. This study showed that a good correlation exists between flow-cytometric, pathological and clinical data.

Cell Division↗
PubMed1990

Effects of angular speed in responses of Paramecium tetraurelia to hypergravity.

The paper shows the results of investigations carried out in a single cell organism. Paramecium tetraurelia exposed to different gravitational levels. Hypergravity resulted in a decrease in cell growth rate. The responses depend on g level and angular speed of the centrifuge; furthermore they depend also on small short fluctuations in g levels, delta g, due to the swimming of the cells inside the culture tubes. Delta g depends on angular speed and size of the holding device. The inhibitory effect of hypergravity, for the same angular speed, increases with respect of the diameter of the culture tubes.

Animals↗
PubMed1985

Some ultrastructural aspects of the vitreoretinal juncture.

The ultrastructural study of the vitreoretinal juncture was carried out by comparing two groups of patients: 6 young subjects under 25 years and 6 older subjects over 70. Retinal samples were taken from the posterior pole, the equator and the extreme periphery. Our work shows that the morphological modifications of the vitreoretinal juncture during the aging process vary following location. The most original alteration, never observed before, appears in the equatorial region: it consists of a widening of the intercell space filled with fibrils adhering to Müller's cells. It builds up an adhesion zone between the vitreous and the retina which is not visible during clinical investigations; it can create a tear during the posterior vitreous detachment.

Adolescent↗
PubMed1985

[Alveolar paraffinosis: cytologic and biochemical study of bronchiolo-alveolar lavage fluid].

A case report of a diffuse alveolar lipoid pneumonia occurring in a patient incapable of giving a proper history underlines the diagnostic difficulty of lipoid pneumonias. Till now, unless the diagnosis was made at necropsy, one relied on a history of prolonged consumption of medications containing mineral oil, with evidence on open lung biopsy of excess fatty material in the pulmonary parenchyma. Chromatography on thin slices of the lipid extract of bronchiolo-alveolar lavage liquid fixed in silica gel, a simple technique, should rapidly give the diagnosis. In the alveolar form of the disease bronchopulmonary lavage returns a significant quantity of paraffin oil and may be considered as a therapeutic method.

Bronchi↗
PubMed1983

[Ultrastructural study of the photoreceptors of the human retina during aging].

The ultra-structural study of the photoreceptors in the human retina during the aging process was carried out by comparing two groups of patient: 6 young subjects under 25 years of age, and 6 older subjects over 70. Retinal samples were taken from the posterior pole and treated with the classical techniques of electron microscopy. Our works show that during the aging process, nuclear and cytoplasmic morphological modifications are observed. The observation about nuclear modifications is in full agreement with aging process theories according to which the genome plays an essential part. On the other hand, no modification of the external article could be so far observed. Further works will perhaps allow to discover a decrease of the renewal process of the photoreceptor discs.

Adolescent↗
PubMed1983

[Ultrastructural aspects of the dormant Artemia embryo].

The ultrastructure of the Artemia cyst and larval organism was investigated. The morphology of the blastomere and of the cell organelles was described. Investigations showed the presence of two mitochondria populations: one located in the cytoplasm, the other one embedded inside the yolk platelets. Relations between yolk and mitochondria are more obvious when considering the first steps of embryonic development.

Animals↗
PubMed1980

[Effect of ultraviolet irradiation on infrastructure and mitotic activity of Tetrahymena pyriformis].

Effects of U.V. irradiation, 3,600 erg/mm2, administrated at a low dose rate, over 75 mn at the very beginning of the cell cycle, were investigated in Tetrahymena pyriformis. Irradiation results in mitotic activity changes, followed either by cell death or cell survival with subsequent normal division activity. Nucleolar fusion, possible intracytoplasmic extrusion of nucleolar aggregates and particular pictures of nucleologenesis are described. Simultaneous cytoplasmic lesions can contribute to the delayed death of Tetrahymena after U.V. irradiation.

Animals↗