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Biomedical subjects

M Nigro

Publications and source records attributed to M Nigro.

At least 73 records · Page 4Linked to original sources
PubMed1982

Evidence of male germ cell redifferentiation into female germ cells in planarian regeneration.

The source and fate of blastema cells are important and still unresolved problems in planarian regeneration. In the present investigation we have attempted to obtain new evidence of cell dedifferentiation-redifferentiation by using a polyploid biotype of Dugesia lugubris s.l. This biotype is provided with a natural karyological marker which allows the discrimination of triploid embryonic and somatic cells from diploid male germ cells and from hexaploid female germ cells. Thanks to this cell mosaic we previously demonstrated that male germ cells take part in blastema formation and are then capable of redifferentiating into somatic cells. In the present investigation sexually mature specimens were transected behind the ovaries and the posterior stumps containing testes were allowed to regenerate the anterior portion of the body. Along with the usual hexaploid oocytes, a small percentage (3.2%) of tetraploid oocytes were produced from regenerated specimens provided with new ovaries. By contrast only hexaploid oocytes were produced from control untransected specimens. The tetraploid oocytes are interpreted as original diploid male germ cells which following the transection take part in blastema formation and then during regeneration redifferentiate into female germ cells thus doubling their chromosome number as usual for undifferentiated cells entering the female gonad in this biotype.

Animals↗
PubMed1979

[Acute myeloid leukemia with megakaryocytic predominance and malignant megakaryocyte proliferation. Apropos of 3 cases].

Three cases of acute myeloid leukemia with megakaryocyte predominance are reported. In the first case megakaryocytosis was particularly evident in bone marrow, liver and spleen. In the second case high content of megakaryocytes was observed in the bone marrow and spleen, during the preleukemic phase only. Third case exhibited a strong predominance of megakaryocytes exclusively within the bone marrow. The characteristics of such observations and their nosologic position within myeloproliferative disorders group are discussed, with special reference to modern views concerning myeloid leukemia.

Adult↗
PubMed1979

[Presence of clusters of Langerhans cells and lymphoid cells in the peritumoral infiltrate of a case of basal cell naevus syndrome. Ultrastructural study (author's transl)].

A case of naevoid basal cell carcinoma syndrome with clusters of Langerhans' and lymphoid cells in the inflammatory peritumoral infiltrate, is reported. Electron microscopy shows intercellular contacts between eight to ten lymphoid cells and a single Langerhans' cell. These contacts occur over limited areas of the cell membranes by means of zones of high electron density on the outer edge of the cytoplasm. The functional significance of this finding is discussed, bearing in mind that recent observations have established certain analogies between Langerhans' and interdigitating reticulum cells. The latter might, within the thymus-dependent region of the lymph nodes, contribute to the formation of a micro-environment favourable to certain immunological activities of T-lymphocyte populations.

Adolescent↗
PubMed1978

Central nervous system lesions in childhood leukemia.

Central nervous system (CNS) lesions were found in 85 of 91 children with acute leukemia. Cerebral atrophy was the most common lesion, occurring in 65 percent. Atrophy was most severe in children treated with intrathecal methotrexate alone or in combination with radiation therapy, in children youngest at time of onset of leukemia, and in children in whom duration of leukemia was shortest. Longer duration was the determining factor among children who were older at onset. Lesions previously reported by other investigators, such as leptomeningeal infiltration of leukemic cells, infection, hemorrhage, degenerative grey and white matter disease and leukoencephalopathy were also seen. Central pontine myelinolysis occurred in four children.

Age Factors↗
PubMedDate not supplied

Impaired NADH-CoQ reductase activity in a child with moyamoya syndrome.

A 33-month-old boy with recurrent stroke-like episodes had angiographic features characteristic of moyamoya syndrome. Mitochondrial encephalomyopathy was suspected because of lactic acidosis and ptosis. Studies of oxidative metabolism on isolated skeletal muscle mitochondria revealed impairment of NADH-coenzyme Q reductase activity. Mitochondrial metabolic disorders may cause moyamoya syndrome when other known associated factors are absent.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Variations of antioxidant efficiency and presence of endosymbiotic diatoms in the Antarctic porifera Haliclona dancoi.

The role of endosymbiotic diatoms as pro-oxidant stressors in porifera has been investigated in the Antarctic sponge Haliclona dancoi in which the presence of diatoms is influenced by marked seasonal variations during the austral summer. Both chlorophaeopigments and frustules were absent in sponge tissues sampled in early November at the beginning of the summer and increased from the mid of December with slightly shifted temporal trends. The efficiency of antioxidant defenses in the sponge showed a marked response to symbionts with clearly enhanced values corresponding to the peak of diatoms.

Analysis of Variance↗
PubMedDate not supplied

Oxidative stress in ecotoxicology: from the analysis of individual antioxidants to a more integrated approach.

An integrate approach will be discussed for investigations on oxidative stress in xenobiotic toxicity. While the analysis of individual antioxidants is useful for their sensitivity and to understand the mode of action of a stressor, the integration with the analysis of the total antioxidant capacity provides a more holistic assessment of the overall biological significance of such variations. TOSC has a greater predictive value on the health condition of the organisms and allows to discriminate the different role of specific ROS in oxidative stress syndrome.

Animals↗
PubMedDate not supplied

Induction of DNA strand breakage and apoptosis in the eel Anguilla anguilla.

The ability of benzo[a]pyrene, Aroclor 1254, 2-3-7-8-tetrachlorodibenzo-p-dioxin and beta-naphthoflavone to induce DNA strand breaks (SB) and apoptosis in erythrocytes of the European eel (Anguilla anguilla) was investigated following by in vivo exposure. DNA damage was evaluated by the Comet assay, while the diffusion assay was used to investigate the induction of apoptosis 7 days after a single intraperitoneal administration. 2-3-7-8-Tetrachlorodibenzo-p-dioxin induced the highest genotoxic effect, followed by benzo[a]pyrene, while the other two substances had limited effects. A significant induction of apoptosis was observed at the highest doses after exposure to benzo[a]pyrene, when DNA damage was also elevated. The occurrence of apoptotic cells after exposure to Aroclor, 2-3-7-8-tetrachlorodibenzo-p-dioxin and beta-naphthoflavone was quite variable and did not show clear dose-related responses. The role of oxidative stress in mediating DNA damage was also discussed.

Anguilla↗