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Biomedical subjects

E Menichini

Publications and source records attributed to E Menichini.

At least 19 recordsLinked to original sources
PubMed1999

Ribosomal RNAs synthesized by isolated squid nerves and ganglia differ from native ribosomal RNAs.

The large rRNA of the squid comprises two chains that may be dissociated by heating at 65 degrees C. A single chain constitutes the small rRNA. Surprisingly, the RNAs synthesized by dissected squid fin nerves and stellate nerves and ganglia differed in size from native rRNAs and did not manifest thermal instability. Nonetheless, they resembled native rRNAs in relative abundance, subcellular distribution, lack of poly(A), and metabolic stability. In addition, newly synthesized RNA was localized in nerve and glial cells, as shown by autoradiographic analysis, and was assembled into 80S ribosomes, which supported the synthesis of neuron-specific neurofilament proteins. Following incubation of nerves and ganglia for >10 h, native rRNAs started to disappear, while two major newly synthesized RNAs progressively accumulated. As a result, after 20 h, native rRNAs were substituted by the two novel RNAs. With use of 32P-cDNA synthesized from the latter RNAs as a probe, the novel RNAs demonstrated a considerable degree of homology with native rRNA in northern analysis. Taken together, the data suggest that in dissected squid nerves and ganglia, the synthesis of native rRNAs is gradually terminated while two novel rRNAs are being synthesized, presumably as a correlate of reactive gliosis and/or neuronal degeneration/regeneration.

Animals↗
PubMed1992

Urban air pollution by polycyclic aromatic hydrocarbons: levels and sources of variability.

The atmospheric levels of polycyclic aromatic hydrocarbons (PAHs), measured since the mid-1970s from approximately 60 towns world-wide, are reviewed. For each investigation, a concise description of sampling conditions and analytical methods is also given. The strongly carcinogenic benzo[a]pyrene was typically found in the range of 1-20 ng/m3 in Europe, and around 1 ng/m3 in the USA. For other PAHs, individual concentrations were generally in the range of 1-50 ng/m3 in Europe, 0.1-1 in North and South America and in Australia, 1-10 in Japan, and 10-100 in two towns in India and New Zealand. Data on the size distribution of PAH-containing particles are also presented, showing that PAH content is adsorbed mostly on respirable particles. The ratios of winter to summer levels, and of urban to rural levels, were found in the range of 2-10 in both cases. PAH levels have progressively decreased in the last few decades, most probably due to the introduction of anti-smoke regulations and the decrease of coal burning for heating. Measurements from different investigations can only be compared with great prudence, owing to sampling factors which can affect results. Sources of urban PAH contamination and of the variability in levels are discussed.

Air Pollutants↗
PubMed1991

Reliability assessment of a gas chromatographic method for polycyclic aromatic hydrocarbons in olive oil.

A quality control test was developed for a gas chromatographic method to determine polycyclic aromatic hydrocarbons in olive oil. Fifteen oil specimens were fortified with eight three- to six-ring polycyclic aromatic hydrocarbons at levels of between 3.0 (approximate detection limit) and 360 micrograms/kg. Three sets of five equally fortified specimens were obtained and assayed at random by three operators. For each fortification level, the means of recovery yield were in the range 56-107%, and were independent of the polycyclic aromatic hydrocarbon congener specificity and the operator's capability. Excluding subsets of data associated with both the fortification level at the detection limit and a deviant polycyclic aromatic hydrocarbon term (benzo[ghi]perylene), an overall mean accuracy of 96% and a precision of 7% were achieved.

Chromatography, Gas↗
PubMed1991

Active polysomes in the axoplasm of the squid giant axon.

Axons and axon terminals are widely believed to lack the capacity to synthesize proteins, relying instead on the delivery of proteins made in the perikaryon. In agreement with this view, axoplasmic proteins synthesized by the isolated giant axon of the squid are believed to derive entirely from periaxonal glial cells. However, squid axoplasm is known to contain the requisite components of an extra-mitochondrial protein synthetic system, including protein factors, tRNAs, rRNAs, and a heterogeneous family of mRNAs. Hence, the giant axon could, in principle, maintain an endogenous protein synthetic capacity. Here, we report that the squid giant axon also contains active polysomes and mRNA, which hybridizes to a riboprobe encoding murine neurofilament protein. Taken together, these findings provide direct evidence that proteins (including the putative neuron-specific neurofilament protein) are also synthesized de novo in the axonal compartment.

Animals↗
PubMed1988

Circadian oscillations of DNA synthesis in rat brain.

The possibility that the synthesis of brain DNA undergoes a circadian fluctuation was examined in male adult Wistar rats, kept under natural lighting conditions or born and raised under artificial lighting conditions. Groups of rats were taken every 4 h during the 24 h, injected subcutaneously with [methyl-3H]thymidine and killed 4 h later. By cosinor analysis, the DNA specific activity of cerebral hemispheres and brainstem was found to show a significant 24 h rhythm with the peak at the beginning of the dark period (waking period). By contrast, in kidney, the peak of the circadian rhythm of DNA specific activity occurred during the light period (sleep period), in agreement with literature data. On the other hand, in 4-week-old rats, born and raised in artificial lighting conditions, brain DNA specific activity followed a 12 h rhythm, in agreement with the lack of a significant diurnal oscillation of the sleep--waking structure. It is concluded that brain DNA synthesis undergoes a circadian fluctuation in association with the circadian rhythm of waking.

Aging↗
PubMed1986

Paradoxical sleep deprivation of the mother enhances DNA synthesis in fetal rat brain: autoradiographic and biochemical evidence.

Pregnant rats were deprived of paradoxical sleep for 3 days starting on the 18th gestational day. The condition of PS-D was imposed by confinement on a small platform surrounded by water or by daily injections of clomipramine. Four hours before the killing rats received a s.c. injection of [3H]-thymidine. The amount of radioactive DNA determined by autoradiography in several regions of fetal brain was found to be markedly increased under both experimental conditions in comparison with the control fetal brain. Considerably more limited effects were observed in kidney. Comparable changes of lower magnitude were obtained by comparing the specific radioactivity of DNA samples purified by chlorophorm extraction and digestion with RNase and proteinase K. The results fully confirm our previous data obtained under similar experimental conditions but based on the analysis of an acid-washed DNA fraction.

Animals↗
PubMed1977

[Isochroman-4-spiro-4'-piperidine: synthesis and analgesic properties].

The synthesis of some isochroman-4-spiro-4'-piperidines by intramolecular O-methylation of 4-aryl-4-hydroxymethylpiperidines with formaldehyde and their analgesic activity ("hot plate"test in mice) are reported. The introduction of the new ring led to compounds with weak analgesic activity.

Analgesics↗
PubMedDate not supplied

Polycyclic aromatic hydrocarbons in olive oils on the Italian market.

The six olive oils and seven virgin olive oils which are most consumed in Italy were analysed for 28 polycyclic aromatic hydrocarbons (PAHs). The aim was to evaluate whether a carcinogenic hazard for the general population can derive from the dietary intake of this food, which is consumed particularly highly in the Mediterranean area. The analytical method involved extraction by liquid-liquid partition, filtration on silica gel, clean-up by thin-layer chromatography on silica gel, and analysis by high-resolution gas chromatography with a flame ionization detector. The 3- and 4-ring PAHs which are most abundant in the environment were found in all samples, at individual levels up to ca. 40 micrograms/kg (for phenanthrene); no important difference was observed between olive oils and virgin olive oils. PAHs which are most suspected of being carcinogenic for humans were not detected (limit of detection, ca. 3 micrograms/kg). The average yearly intake of the detected PAHs through this food was estimated at ca. 0.56 mg per capita.

Chromatography, Gas↗
PubMedDate not supplied

[Safety forms for industrial lubricating oils: a working proposal at the national level].

The health and safety data sheets for lubricating oils currently in use present considerable differences regarding the information they provide. Often, the information is either too generalized or incomplete--particularly on the chemical aspects of oils--and therefore the sheets are inadequate for the prevention and control of the occupational risks. For the purposes of harmonization, a data sheet has been prepared which takes into account the specific features of the products, and particularly the handling of confidential data. The most important oil manufacturers have been consulted, and they have agreed to use the data sheet in order to provide information on their products to the local health authorities. The widespread use of this data sheet should enable an easier comparison of the health and safety data of oils to be made, provide a better understanding of the information received and, consequently, evaluate the risks involved.

Confidentiality↗
PubMedDate not supplied

Circadian rhythms of DNA content in brain and kidney: effects of environmental stimulation.

Male adult Wistar rats kept under natural lighting show circadian rhythms of DNA content and DNA synthesis in the cerebral cortex, cerebellum and kidney. In the cerebral cortex the acrophases of the 2 rhythms almost coincide during the dark period. On the other hand, in kidney, the acrophase of DNA synthesis is phase-advanced by about 14 h with respect to the acrophase of DNA content, which occurs in the dark span, as in the cerebral cortex. Comparable results were obtained in 5 week-old rats raised under artificial lighting conditions (LD 7:19) and exposed for a few days to sensory and social stimulation (an enriched sensory environment). At variance with the latter data, the circadian changes of DNA content and synthesis flattened out and were not statistically significant in the cerebral cortex of 5 week-old rats kept for a few days under conditions of sensory and social deprivation (an impoverished sensory environment). A similar effect occurred in kidney with regard to the rhythm of DNA content, while the circadian rhythm of DNA synthesis remained statistically significant but was phase-delayed by about 6h with respect to the corresponding rhythm occurring in the enriched environment. In sensory impoverished rats, MESOR values of kidney wet weight and DNA specific activity were significantly higher than in sensory enriched rats, while MESOR values of DNA content were significantly lower. The data demonstrate the striking dependence of the circadian variations of DNA content and synthesis on the nature of environmental stimulation.

Animals↗