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Biomedical subjects

C Taddei

Publications and source records attributed to C Taddei.

At least 55 records · Page 3Linked to original sources
PubMed1987

Acetylcholinesterase in neuroblastoma and neuroblastoma x glioma hybrid cells: cellular localization and molecular forms.

The cellular localization of acetylcholinesterase (AChE) was investigated at the electron microscope (E.M.) in a neuroblastoma and neuroblastoma x glioma hybrid line, which differ for their ability to establish synaptic contacts. Only cells of the latter line show association of AChE to the plasmamembrane, while in the former the activity is mainly intracellular. Sucrose sedimentation analysis of AChE molecular forms has shown no significant differences in the distribution of the two forms, G2 and G4, between the two cell lines. On the contrary a marked difference is observed in the ability of the cell to release the enzyme in the culture medium. In fact the cells lacking AChE on their surface release in the medium a much higher proportion of their enzyme, than the cells showing AChE association to their plamamembrane. The possible role of two alternative fates for AChE, secretion or membrane insertion, in determining the observed differences of enzyme localization is discussed.

Acetylcholinesterase↗
PubMed1985

In vitro generated mast cells express natural cytotoxicity against tumour cells.

Bone marrow cells from mice were cultured in vitro in the presence of interleukin-3 (IL-3). After 2 weeks, the majority of the cells differentiated towards mast cells as judged by morphological and biochemical criteria. When populations of 99% IL-3-dependent mast cells (IL-3 MC) were tested for their anti-tumour activity in vitro, it was found that they can express natural cytotoxicity (NC) but not other natural reactivities. Moreover, the effector cells were not positive for Thy 1, Lyt 1 and Lyt 2 markers. The capability of mast cells to express NC activity seems to be related to their in vitro differentiation, since mast cell deficient W/Wv mice had normal NC activity. Thus, IL-3 MC must be added to the variety of cells capable of expressing natural anti-tumour reactivities in vitro.

Animals↗
PubMed1984

The modifications of cortical endoplasmic reticulum during in vitro maturation of Xenopus laevis oocytes and its involvement in cortical granule exocytosis.

In Xenopus laevis eggs, cisternae shells which surround cortical granules (CG) are part of a cortical endoplasmic reticulum (ER) network. In this paper the origin of such ER shells has been studied in full-grown, progesterone-exposed Xenopus oocytes. Furthermore, the possible role of the cortical ER in the activation process has been investigated by pricking maturing oocytes. It has been shown that in full-grown ovarian oocytes ER CG shells are absent and ER cisternae are extensively and randomly distributed throughout the peripheral cytoplasm, where they appear to be continuous with annulate lamellae (AL). Following hormone treatment, the AL completely disaggregate and the ER cisternae gradually migrate to the cortex where they surround the CG constituting the typical cortical network described in uterine eggs. Furthermore, it has been found that 8 h after progesterone treatment (before the first polar body extrusion) the response to pricking (CG exocytosis) occurs only at the animal half; there is no observable response in the vegetal half. At this time ER shells surround CG only in the animal hemisphere. A complete CG exocytosis occurs following the first polar body emission, when the cortical ER is well organized in the whole oocyte cortex. The correlation between the differentiation of the cortical ER and the arousal in the oocyte of the ability to respond to a pricking stimulus is discussed in the light of an involvement of the cortical ER in the propagation of CG exocytosis.

Animals↗
PubMed1982

Ultrastructural observations of polyoma infected Friend erythroleukemic cells.

Friend erythroleukemic cells (FLC) infected by Polyoma (Py) virus were studied at the electron microscope both during their lytic cycle, which occurs within the first 96 hr after infection, and in the surviving stabilized cells 30 days after infection. The results showed that the Polyoma virus and Friend leukemic virus (FLV) coexist and mature together in the same cell. During the lytic cycle, the Py particles were scattered in the nucleoplasm, and sometimes they were also found aggregated into crystals. Instead crystalline aggregates of Py particles were always present in the few surviving virus-carrying cells 30 days after infection. A possible interpretation could be that the crystal aggregation serves to maintain the viruses in a latency that allows the survival of the host cells.

Animals↗
PubMed1978

Intercellular bridges between follicle cells and oocyte during the differentiation of follicular epithelium in Lacerta sicula Raf.

Intercellular bridges first appear during lizard oogenesis when follicles are rather small (150 microgram in diameter); at this stage they form connecting links between the oocyte and follicle cells, which have not yet differentiated into pyriform cells. Later on, when the follicles have become larger (1 mm) and the follicular epithelium appears constituted by 3 types of cells (small, intermediate and pyriform cells) they form connecting links between the oocyte and both intermediate and pyriform cells. The establishment of intercellular bridges between pyriform cells and the oocyte precedes the complete differentiation of the former, which excludes the possibility that the fusion between pyriform cells and oocyte occurs only after these cells are completely differentiated. In still larger follicles (up to 2 mm in diameter), during the degeneration of the pyriform cells, the occurrence, inside the bridges, of mitochondria and other cytoplasmic material suggests that these cells at the end of their function transfer their contents into the oocyte.

Animals↗
PubMed1977

Progesterone-induced DNA polymerase activity in full-grown oocytes of Xenopus laevis (1).

DNA polymerase activity increases in full-grown oocytes of Xenopus laevis during in vitro progesterone-induced maturation. This increase is inhibited by cycloheximide. The presence of the oocyte's nucleus (germinal vesicle) seems essential for the induction of this increase: in previously enucleated oocytes, the level of DNA polymerase activity does not change during progesterone treatment. Furthermore, a new form of DNA polymerase is detectable by DEAE chromatography in in vitro matured oocytes.

Animals↗
PubMed1976

Intercellular bridges in lizard oogenesis.

Study of the germinal epithelium in the adult lizard shows that the germ cells constitute clusters of synchronized cells interconnected by intercellular bridges. Such bridges interconnect oogonia as well as early meiotic prophase oocytes (zygo-pachitene). Besides true intercellular bridges in oocytes, there are plasma membrane interruptions forming large zones that ensure cytoplasmic continuity between adjacent cells. In early diplotene, germ cells are isolated. Later, during auxocytosis, when the polymorphic follicular epithelium around the oocyte starts differentiating, intercellular bridges appear between the follicle cells and oocyte. No relationship is observed between the intercellular bridges found in the germinal epithelium and those found between the follicle cells and oocyte.

Animals↗
PubMedDate not supplied

[Cost of ICU in Italy. Results from an empirical study on a sample of 12 hospitals].

BACKGROUND: The Italian hospital payment system based on DRG doesn t properly include Intensive Care Units (ICU) costs. Since great emphasis has been recently given to rationing health care resources, assessing ICU costs seems to be dramatically relevant. Aim of the study was to assess the average yearly cost and the cost per diem of a sample of Italian multispecialistic ICU wards. METHODS: In September 1995, a questionnaire concerning data on variable and fixed cost was sent to 25 Italian ICU wards, 11 NHS hospital-based (Northern Italy: 5; Central Italy: 4; Southern Italy: 2) and 14 school of medicine-based (Northern Italy: 7; Central Italy: 5; Southern Italy: 2). Variable cost data included: disposable, drugs, blood and blood-derived products, physical tests, chemical and microbiological routines, instrumental diagnostic procedures and physiotherapy. Concerning fixed costs, data on personnel and equipment were requested. In addition, some hospital overheads data (utilities; power; heating; maintenance; cleaning; laundry; accounting; waste disposal; cafeteria) were collected. RESULTS: On the basis of the 12 questionnaires returned (Northern Italy: 9; Central Italy: 3; Southern Italy: 0), the yearly cost of an ICU ward is Liras 4,580,032,000 (range 2,739,277,000-7,704,292,000), whereas the average cost per diem is Liras 1,802,000 (range 1,234,000-3,179,000). Cost of personnel is about 61% of the above mentioned costs. CONCLUSIONS: Despite the lack of questionnaires from Southern Italy and the unavailability of some data concerning both the cost of equipment and the overheads, the remarkable average cost values obtained could support further research.

Costs and Cost Analysis↗