Biomedical subjects

C Sbrana

Publications and source records attributed to C Sbrana.

9 recordsLinked to original sources

PubMed2000

Adhesion to hyphal matrix and antifungal activity of Pseudomonas strains isolated from Tuber borchii ascocarps.

Pseudomonas spp. isolates from Tuber borchii ascocarps, known to be able to produce phytoregulatory and biocontrol substances in pure culture, were used to perform studies on their possible physiological role in nature. Antimycotic activity was confirmed against fungal contaminants isolated from the ascocarps, suggesting that populations associated with Tuber borchii fruit bodies may play a role in the maintenance of ascocarp health. Fifty-five percent of strains tested were also able to release metabolites which affected T. borchii mycelial growth and morphogenesis in culture. On the contrary, growth of the arbuscular mycorrhizal fungus Glomus mosseae and the ectomycorrhizal fungus Laccaria bicolor, putative competitors of Tuber for mycorrhizal infection sites on roots, was not influenced by the presence of any bacterial strain. The possibility that these bacteria, which show antifungal activity and fungal growth modulation activities, might be incorporated in the developing ascocarp by means of their preferential adhesion to Tuber mycelium is discussed.

Ascomycota↗

PubMed1998

Cellular events involved in survival of individual arbuscular mycorrhizal symbionts growing in the absence of the host

A survival strategy operating in the absence of the host was shown in obligately biotrophic arbuscular mycorrhizal (AM) symbionts. When no host-derived signals from the surrounding environment were perceived by germinating spores, fungal hyphae underwent a programmed growth arrest and resource reallocation, allowing long-term maintenance of viability and host infection capability. The early stages of mycelial growth of AM fungi were studied by a combination of time-lapse and video-enhanced light microscopy, image analysis, and immunodetection, with the aim of acquiring knowledge of cell events leading to the arrest of mycelial growth. The time-course of growth arrest was resolved by precisely timing the growth rate and magnitude of the mycelium originating from individual spores of Glomus caledonium. Extensive mycelial growth was observed during the first 15 days; thereafter, fungal hyphae showed retraction of protoplasm from the tips, with formation of retraction septa separating viable from empty hyphal segments. This active process involved migration of nuclei and cellular organelles and appeared to be functional in the ability of the fungus to survive in the absence of a host. Immunodetection of cytoskeletal proteins, metabolic activity, and the retention of infectivity of germinated spores confirmed the developmental data. The highest amounts of tubulins were detected when hyphal growth had ceased but when retraction of protoplasm was most active. This was consistent with the role of the cytoskeleton during protoplasm retraction. Succinate dehydrogenase activity in hyphae proximal to the mother spore was still detectable in 6-month-old mycelium, which remained viable and able to form appressoria and produce symbiotic structures.

Journal Article↗

PubMed1996

Potentiation of occupational carbon tetrachloride toxicity by ethanol abuse.

1. Two separate cases of acute occupational poisoning following exposure to vapours of a fire extinguishing liquid are described. Analytical, clinical, pathological and toxicological data leave little doubt that toxicity was due, in both cases, to inhalation of carbon tetrachloride present at high concentrations ( > 15% and 78% by weight, respectively) in the fire extinguishing liquid. 2. Both subjects were admitted to hospital, 4 and 8 days after exposure, respectively, and developed severe hepato-nephrotoxicity with hepatomegaly, increased values of serum transaminases, blood urea nitrogen (BUN), creatinine, gamma-glutamyl-transpeptidase (gamma-GT), bilirubin and uric acid and, finally, anuria. They recovered in about three to four weeks, after several haemodialytic sessions. 3. Interestingly, in both cases the other workers exposed under the same conditions and for the same period of time as the two patients showed no signs or symptoms of toxicity. The reason for the observed different susceptibility to CCl4 is attributable to an abnormally high ethanol abuse by the two workers, as reported in the clinical records and confirmed by their relatives and colleagues (120 and 250 g per day, respectively). Daily ethanol intake by the coworkers was less than 50 g for all subjects. 4. Although the potentiating effect of ethanol on the toxicity of CCl4 is well known in experimental animals, as a result of cytochrome P-450 induction, direct evidence in humans reported in the literature so far was limited by the lack of information, in all published reports, on the presence or absence of effects in non-alcoholic exposed "controls', when these were present.

Adult↗

PubMed1995

Cytogenetic biomonitoring of styrene-exposed plastic boat builders.

Earlier studies have produced evidence for an association between work-related styrene exposure and cytogenetic damage, while more recent studies have failed to show such an association. In the present study, chromosome aberrations (CA) and sister chromatid exchanges (SCE) were measured in peripheral blood lymphocytes of 46 male workers employed in a fiber-reinforced plastic boat building factory and exposed to styrene. Two groups of 23 workers each, characterized by different exposure levels (ranges: 2-120 mg/m3 and 86-1389 mg/m3 ambient air) were studied, fifty-one controls matched by sex, age and smoking habits were included. Randomized blood samples were analyzed for cytogenetic damage separately in two laboratories. Interlaboratory differences in the scoring of CA and SCE were noted. However, increases of the considered cytogenetic endpoints in exposed vs control groups were consistently observed in both laboratories. Multivariate statistical analysis of pooled data revealed increases of CA ranging between 19% (RR = 1.19; 95% C.I., 0.80-1.78; chromatid-type aberrations, low exposure group) and 144% (RR = 2.44; 95% C.I., 1.26-4.70; chromosome-type aberrations, high exposure group). Parallel excess of SCE in styrene exposed workers was also observed, although at a lesser extent (RR = 1.22; 95% C.I., 1.05-1.43, low exposure group; RR = 1.26; 95% C.I., 1.07-1.47, high exposure group). These findings suggest the presence of a causal association between occupational exposure to styrene and cytogenetic damage in the plastic boat building factory that was the object of the study.

Adult↗

PubMed1993

N-acetylcysteine inhibits diesel extract mutagenicity in the Ames test and SCE induction in human lymphocytes.

N-Acetylcysteine (NAC) has been reported to decrease genotoxicity induced by several mutagens. In this paper, the desmutagenic effect of NAC on a complex mixture, such as diesel extract, has been analyzed. Studies have been carried out in vitro with the Ames test (reverse mutations on TA98, TA100, and TA104 strains) and sister chromatid exchanges assay (SCE) in human lymphocytes. NAC inhibits diesel genotoxicity in both assays. NAC also inhibits the mutagenicity of 1,8-dinitropyrene (1,8-DNP) and 1-nitropyrene (1-NP) known to be present in diesel exhaust and to be activated by cellular O-transacetylases and nitropyrene reductases. NAC inhibits also the induction of SCE in human lymphocytes by diesel extract. These results, and those obtained by the preincubation of NAC with cells, suggest that the inhibition also takes place inside the cell.

Acetylcysteine↗

PubMed1992

The analysis of the joint effect of substances on reversion systems and the assessment of antimutagenicity.

The statistical methods for the analysis of mutagenicity and carcinogenicity underwent considerable theoretical-practical development following the need for assessing the mutagenic and carcinogenic potential of substances. Antimutagenicity is investigated through the analysis of respondents in dose-response assays, when two different molecules are administered separately and as a mixture to a respondent system. When the number of respondent units is high, and doses are orthogonal, it is possible to apply simple models such as analysis of variance. This is not always possible or common, and alternative approaches have been developed, based on multiple regression and on tables of proportions. In this work, some of the most frequently used methods for the assessment of joint responses are reviewed, particularly those based on multiple regression, such as the method of Shaeffer et al. and the method of Hass et al. In order to illustrate these methods, joint responses of perylene and cyclopentapyrene, of N-acetylcysteine and dinitropyrene, and of N-acetylcysteine and extracts from diesel exhausts were analyzed. An antagonistic effect of perylene on the action of CPP was detected by the algorithm of Shaeffer et al. The effect is not multiplicative, i.e., it is not proportional to the product of doses. The antimutagenic effect of N-acetylcysteine on dinitropyrene is multiplicative, as detected by the method of Hass et al. The latter reveals that the inhibition by N-acetylcysteine on the mutagenic effect of extracts from diesel exhausts is also multiplicative.

Acetylcysteine↗

PubMed1988

Effects derived from long-term low-level chromium exposure in ferro-alloy metallurgy. Study of absorption and renal function in workers.

Ferro-chromium production is based on the use of chromium oxide (III) and it is generally accepted that chromium in this form is not able to cross biological barriers. However, the data on the toxic and carcinogenic effects of hexavalent chromium in man are now firmly established. Some studies have questioned these data, calling for a clarification as to whether exposure to trivalent chromium can also produce human effects, perhaps with different latency time. A study was carried out on the exposure conditions (type and degree) in a ferro-chromium foundry that had been in operation since 1972. The absorption levels in the working population of the foundry, and the possible toxic effects on the kidney have been investigated. A total of 236 workers (142 employed in production departments, 33 office workers and 61 sub-contractor employees) were examined with measurement of the indicators of dose (urinary-chromium) and of effect on the kidney (albumin, retinol binding protein, and renal tubular epithelium antigens in the urine). Environmental hygiene measurements showed relatively low values of total chromium in the air (always less than 0.160 mg/m3). Hexavalent chromium was absent or, if present, at levels below the sensitivity of the analytical method used (0.001 mg/m3). The values of urinary chromium measured at the beginning and at the end of the working day and at the end of the work shift were always less than 5 micrograms/g creatinine, which has been proposed as a biological limit in chromium exposure. However, differences were observed between groups of subjects employed on different jobs, which is indicative of an absorption process varying according to the degree of exposure. The indicators of effect did not reveal any renal impairment, even early, that could be attributed to the toxic action of chromium.

Adult↗

PubMed1982

[Not Available].

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History, Ancient↗

PubMedDate not supplied

[Cross-over epidemiologic study of symptoms and respiratory function in workers at a furniture factory].

An epidemiological survey on symptoms and diseases (collected with CNR standardized questionnaire) and on lung function (forced vital capacity and derived indexes; CO diffusing capacity) has been carried on in workers of a furniture plant in Arezzo. Significantly higher prevalence rates of cough in smokers than in non smokers, and of cough, phlegm, wheeze in non smoker workers than in the control group from a general population sample were present. A not significant relationship of symptoms and working years was also found. Lung function indices were in the normal range; smokers had significantly lower values than non smokers. A lower FEV1%, after adjusting for age and smoking, was shown by subjects with more working years. Thus, in a modern furniture plant the risk of adverse health effect seems to be slight: this conclusion may be confirmed by the ongoing longitudinal survey.

Adult↗