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Biomedical subjects

L Santi

Publications and source records attributed to L Santi.

At least 73 records · Page 4Linked to original sources
PubMed1990

Mortality from specific causes among silicotic subjects: a historical prospective study.

A historical mortality study was conducted among 520 silicotic subjects diagnosed at the Department of Occupational Health of the San Martino Hospital, Genoa, Italy, between 1961 and 1980. Vital status was ascertained as of 1 January 1982. Age-, sex- and calendar-year-adjusted standardized mortality ratios (SMRs) for specific causes were computed using Italian as well as Genoa County male population death rates. The study shows statistically significant increased mortality from all deaths (SMR = 2.92), all cancers (SMR = 2.38), respiratory tract cancers (SMR = 6.85), respiratory tract diseases (SMR = 13.63), and from 'other diseases' (SMR = 6.81). The excess mortality from respiratory tract diseases and from 'other diseases' are mainly attributable to silicosis and silicotuberculosis, respectively. These findings confirm the existence of a causal association between silicosis and increased mortality from both malignant and non-malignant respiratory tract diseases. The high mortality from respiratory tract cancers was still present even after adjustment for smoking.

Adult↗
PubMed1989

The problem of carcinogenic hazard evaluation for new chemicals: general considerations about the carcinogenic process.

We discuss the problem of oncogenic hazard evaluation for new chemicals. In the recent past, assessment of global carcinogenicity in rodents was considered the most significant type of information. It has recently emerged that this type of information is not adequate to distinguish initiation and genotoxicity from promotion-like effects. In this report we suggest that hazards from initiating agents and hazards from promoting agents should be treated separately. In this perspective, longterm experiments for carcinogenicity in rodents should still play an important role but a less central one. Initiation-promotion experiments in different target organs are recommended. We suggest a strategy of hazard evaluation related to the initiating potential as distinct from overall carcinogenicity. The problem of utilizing not only the qualitative component of the available information, but also the quantitative component, is considered. Finally, we discuss a possible hazard evaluation for promoting effects, but conclude that this area is very much in its infancy. Possible contributions of computer science technology to the problem of oncogenic hazard evaluation are briefly introduced.

Animals↗
PubMed1989

DNA damage in mouse and rat liver by caprolactam and benzoin, evaluated with three different methods.

Benzoin and caprolactam were examined for their capability of inducing alkaline DNA fragmentation in mouse and rat liver DNA after treatment in vivo. Three different methods were used. With the alkaline elution technique we measured an effect presumably related to the conformation of the DNA coil. With a viscometric and a fluorometric unwinding method we measured an effect presumably related to the number of unwinding points in DNA. For both compounds only the alkaline elution technique was clearly positive. The results suggest that both caprolactam and benzoin can induce an important change in the conformation of the DNA coil without inducing true breaks in DNA.

Animals↗
PubMed1988

High chemotactic motility and growth in hard agar of a variant of RSV-transformed fibroblasts are lost in late passages.

Cloning efficiency in hard agar (0.6%) and high chemotactic migration toward fibroblast conditioned medium have been shown to characterize metastatic tumor cells. We studied growth in 0.6% agar and chemotaxis of two lines of Rous Sarcoma virus-transformed Balb/c3T3 cells, B77/3T3 (low metastatic) and AA12 (high metastatic), and compared them to their non-transformed counterpart, in order to verify whether these properties were maintained during several subcultivations. Cells were cryopreserved at early passages and thawed for experiments. Both assays were performed on freshly thawed cells (4-6 weeks in culture) and on cells which had been cultured 15-20 weeks after thawing. B77/3T3, which are tumorigenic but low metastatic and which have a very low cloning efficiency in hard agar (0.1-1%), showed a chemotactic response to Balb/c3T3 conditioned medium about two-fold higher than control Balb/c3T3. This response did not change with time in culture. AA12 cells, a genetic unstable variant of B77/3T3 selected for its growth in hard agar (0.6%), had a high cloning efficiency in hard agar and showed a high chemotactic motility (three-fold the controls). High growth in 0.6% agar and high chemotaxis of AA12 were lost in late passages, where cells behaved as the controls. It seems that besides the already reported variation in anchorage-independent growth, genetically unstable tumor cells can also have important variations in chemotactic motility during subcultivations.

Agar↗
PubMed1988

A cohort study of workers employed in a refractory brick plant.

A mortality study was carried out on a cohort of workers who were exposed to silica dust in a refractory brick plant. The cohort was divided into two groups: workers with and without silicosis, and their mortality was contrasted with the death rate of Genova from 1960 to 1979. Results show an increased risk for laryngeal tumors (3 obs., 0.44 exp., SMR = 682), nonmalignant respiratory disease (16 obs., 3.2 exp., SMR = 500), and cardiovascular diseases (19 obs., 11 exp., SMR = 173) among silicotics. The mortality rate for lung cancer showed an increase for the cohort of workers as a whole (11 obs., 6 exp., SMR = 183). The almost double overall mortality observed in silicotic subjects raises some doubts about the validity of other proportional mortality studies that showed no excesses for workers in these industries.

Adult↗
PubMed1988

A new method to reveal the genotoxic effects of N-nitrosodimethylamine in pregnant mice.

DNA damage and repair in kidney and liver of mouse fetuses exposed to selected doses of N-nitrosodimethylamine (NDMA) (CAS No. 62.75.9) were studied using the alkaline elution technique. CD1 female mice (15 days pregnant) were treated i.p. with 2 and 10 mg/kg b.w. of NDMA; a slight increase in DNA damage was observed in their fetuses compared to untreated controls. A 2-fold higher extent of DNA damage was induced when mice were treated by intrafetal injections of a rat S9 activating fraction (S9) immediately before exposure to the same dose of NDMA by transplacental means. The DNA-strand breaks disappeared as a function of time in animals treated with NDMA alone. In contrast, a significant persistence of DNA damage was detected in the liver and lung of fetuses which were treated with S9 and NDMA in sequence. These experiments demonstrate the metabolic immaturity of unborn mice as far as the carcinogenic activation of NDMA is concerned and show the high susceptibility of fetal tissues to DNA-damaging agents. The alkaline elution applied in vivo by the transplacental route combined with the intrafetal injection of an exogenous activating microsomal fraction allow to extend our knowledge on the interaction of metabolism-dependent chemicals with fetal tissues.

Animals↗
PubMed1988

[Study on the attitude and smoking habits of the students of a school for professional nurses].

A study on 285 students and teachers of a nurse professional school was undertaken in two hospital of Genoa. A questionnaire proposed by World Health Organization and by Italian League Against Cancer was employed to collect data on smoking habits and behaviour. Subjects included in the present study were selectively chosen as they are in a transitional phase between school application and working environment within the hospital practice. Although these sample of hospital personnel showed a slow trend toward quit smoking, the rates of smokers are rather high, both in the youth (55%) and in the teachers. Our results showed that 87% of subjects interview agreed with the necessity to avoid smoking within the hospital environment; young nurses generally lack a specific knowledge about the hazard of smoking and more detailed information is requested for a correct education and prevention of patients' health.

Adult↗
PubMed1988

[Teachers and smoking. Methods and results of an awareness and up-dating program in Ligurian schools].

An investigation on smoking habits of teachers of secondary and high schools allowed the collection of very interesting and useful data for the organization of post-graduate up-date courses and health education programs. Smokers' proportion remains still high, as 35% of males and 30% of females teachers are smokers; this situation is different in other countries, where an inverse relationship exists between smoking habit and economic welfare and cultural level. The number of daily-cigarettes was rather low only in females teachers, as 50% smoked less than 5-10 daily-cigarettes. Teachers' interviews suggested the high degree of interest in the organization of health education programs and courses on smoking, with special regard to the courses on smoking, with special regard to the methodology that is required for prevention programs in the school. The high attendance to the courses, the quantity and quality of teachers' reports on these problems and the practical application in school environment of these theoretical concepts confirmed the reliability and effectiveness of this methodologic approach.

Adult↗
PubMed1987

Characterization of the effects induced on DNA in mouse and hamster cells by lithocholic acid.

Lithocholic acid (LCA) is a promoting agent in colon carcinogenesis. In this work we have tried to characterize the DNA alteration induced by LCA in cells grown in vitro and in nuclei. Confirming previous findings, a clear increase in elution rate was observed at both alkaline and neutral pH. The extent of the increase was very similar at the two pHs. However, an increased elution rate could be observed only when lysing the nuclei at high ionic strength and low detergent concentration (2 M NaCl + 0.2% N-lauroylsarcosine sodium salt). No effect could be observed when the nuclei were lysed with a high detergent concentration (2% sodium dodecyl sulfate). In addition, a slight effect could be observed using a method for the evaluation of DNA unwinding in alkali. After termination of the incubation with LCA, the DNA alteration observed with DNA elution disappeared very rapidly both in intact cells and nuclei, even when the incubation buffer was totally unsuitable for the repair of the type of DNA damage induced by typical genotoxic agents. The effect of LCA on DNA was apparently not mediated through an inhibition of topoisomerase II. Only the intact chromatin of nuclei was responsive, not the quasinaked DNA of nuclei lysed at high ionic strength. We advance the hypothesis that the increased alkaline and neutral elution rate observed with LCA could be independent of DNA fragmentation and related to changes in chromatin structure.

Animals↗
PubMed1987

Tissue sampling from the common bile duct through endoscopic retrograde cholangiopancreatography, endoscopic papillo(sphinctero)tomy and drainage in juxtapapillary malignancies.

In 22 patients with radiological evidence of a malignant stricture or an obstruction of the common bile duct, endobiliary tissue specimens were obtained through endoscopic retrograde cholangiopancreatography. An endoscopic papillo(sphinctero)tomy was necessary in 9 of the 22 patients. The following techniques were employed: (1) forceps biopsy of the papillary infundibulum and/or of the common bile duct; (2) brush cytology in the same sites as above; (3) biliary juice cytology obtained by a nasobiliary drainage tube. In 8 patients, two different sampling techniques were used. The final diagnosis was established by means of pathological evaluation of surgical or necroscopic material. The diagnostic adequacy was 100% for biopsy, 88% for brush cytology, and 62% for bile cytology. The sensitivity was 100%, 66%, and 25%, respectively, for the above techniques. From 6 cases without biliary cancer, the specificity was 100%. These data show that biopsy specimens alone provide a definitive preoperative diagnosis in most cases, provided adequate samples are obtained.

Aged↗
PubMed1987

Colorectal cancer in patients with family history.

The relationship between first degree family history of colorectal cancer and some pathological and clinical features was investigated in 302 patients affected by large bowel carcinoma. Patients with inherited forms of polyposis of the large bowel were excluded. Thirty-six (11.9%) had at least one close relative affected by intestinal cancer. No relationship between family history and pathological features (anatomic distribution, stage and grading) was found. Moreover no difference in prognosis between patients with a family history and those without was shown. These results suggest no relationship between a first degree family history and the natural history of the disease.

Adult↗
PubMed1987

Utilization of the quantitative component of the information obtained from short term tests.

We are referring in this paper to traditional tests of genotoxicity that are essentially detecting properties correlated with the initiating activity of chemical and physical agents. In classical initiation-promotion experiments, promotion is changing dramatically tumor frequency, but a better correlation between initiation and tumor frequency may exist when carcinogenesis experiments in rodents utilize only an initiator agent. End points, metabolism and target organs of short term test may be not optimal in respect to the real initiation process. In conclusion, we have to expect a very high level of statistical noise in the correlation between short term tests and carcinogenicity in rodents. Correlations of this type are not unique in science. For instance, the input data for weather forecasting and the real weather are often related with a high level of statistical noise. But this is not considered a good reason for throwing away the quantitative component of the input information. Similarly, in this context the utilization of the quantitative component of the information improves in a moderate, but not negligible way the predictive value of the information offered from short term tests, especially when they are used in a battery. In this review we discuss the possibility that, when studying correlations between genotoxicity tests and carcinogenicity in rodents, a quantitative approach could replace with important advantages the qualitative approach generally adopted up to the present time. The qualitative approach appeared as a more modest but realistic approach to the complexities of these correlation studies. What we suggest is that a quantitative approach mathematically not less correct than the qualitative approach is feasible. More precise and useful information for risk assessment evaluations can be obtained.

Animals↗
PubMed1987

The complementary role of primary prevention, early detection, and therapy in our fight against cancer.

Public health strategies for cancer control are determined by the epidemiological, clinical and biological characteristic of each cancer. Primary prevention is most easily implemented in cancers due to one or few factors. Secondary prevention is best suited for frequent cancers with a long preclinical, detectable phase. Therapy has to be relied upon in rare cancers of unknown etiology. A critical evaluation of the accomplishments of these three approaches shows that the potential role in cancer control of early detection and treatment is severely hampered by the high social and human costs, that are only partially counterbalanced by the limited effectiveness. As a consequence, primary prevention should be regarded as the key approach to cancer control, and efforts should be concentrated on studies concerning cancer etiology and on the implementation of preventive measures.

Female↗