The stability of a genetically modified strain of Fusarium oxysporum used as antagonist against phytopathogenic formae speciales of F. oxysporum was evaluated both in vitro and in microcosm assays. The Escherichia coli hygromycin B phosphotransferase gene (hph), conferring hygromycin B resistance, was introduced by genetic transformation into a recipient strain marked by benomyl resistance and a dark red pigmentation. Hybridization with the complete plasmid suggested that the integration had generally occurred in a multiple‐tandem array at multiple sites. Among nine independent transformants tested, only three of them were mitotically stable after four rounds of vegetative growth with no selective pressure, while six showed various changes in the integration pattern. One transformant had lost the ability to grow in the presence of hygromycin B. In soil microcosms all the transformants maintained the hygromycin B resistant phenotype, but six of them showed rearrangement of transforming DNA. Only one strain (coded T26.40) underwent no obvious rearrangement both after in vitro growth and after recovery from the soil microcosm. The nine transformants were used in three biological control experiments against Fusarium wilt of carnation in comparison to two untransformed reference strains and to the recipient mutant. A high degree of variability in the biocontrol activity was observed throughout the experiments and only transformant T26.40 consistently controlled the incidence of disease. The results are discussed in relation to risk assessment of the release of transgenic antagonistic fungi.
Summary.-The post-operative survival in 554 lung carcinomata, classified according to the histological type, was calculated by the actuarial method. On the whole, squamous cell carcinoma was the most favourable and anaplastic small cell carcinoma the least favourable lesion. However, in tumours smaller than 4 cm, confined to the lung and with negative lymph nodes (stage I), small cell carcinoma had the highest percentage of 5 year survivors, followed by large cell carcinoma, squamous cell carcinoma and adenocarcinoma. When tumours had attained a larger size and/or spread tQ neighbouring structures and regional lymph nodes (stage II and III), the histological type was a much more determining factor in survival, squamous cell carcinoma being a significantly more favourable lesion. On the other hand, no difference in survival in relation to the histological type was found when distant metastases were probably present (stage IV). It was concluded that in assessing the role of histopathology in the prognosis of lung cancer, the mutual relationship to other pathological factors must be taken into account.
(Collier et al., 1958;Spjut et al., 1961;Maamies, 1966;Schottenfield, 1968;Jackman et al., 1969;Bennet et al., 1969; Slack, 1970) has been emphasized by some authors and denied by others.Higgins and Beebe (1967) found that only 4 or 5 out of 40 both clinical and pathological factors examined carried independent information predictive of cancer-free survival at 36 or 60 months. Midorikawa et al. (1968) found that it was difficult to predict the prognosis of resected lung tumours on the basis of pathological examination.This disagreement can be in part explained by the limitations of routine pathological examination (Sherwin, 1966) and more generally with the rather rough definition of some of the studied factors. A second point which seems worthwhile considering is that most of these factors have generally been taken into account one at a time. Some factors may likely play a different role in affecting prognosis whether they are or are not related to other factors.
The pathological features of 405 lung tumors, ascertained on both macroscopic and microscopic examination are reported in detail. On this evidence the tumors were divided into categories by histopathological extent, irrespective of histological type, the aim being to supply a detailed scheme for recording information on the local extent of the disease. In accordance with UICC usage, these categories are denoted by the symbol P. The following 4 P categories are: P1 central or peripheral tumors confined to the lung; P2 tumors involving contiguous structures such as the main bronchus or the visceral pleura, excluding the visceral pleura lining the fissures, which is regarded as included « within » the lung; P3 tumors that have spread to neighbouring structures such as the mediastinal soft tissues and/or viscera (excluding lymph nodes), and chest wall; P4 tumors made up of two or more neoplastic masses within the same lobe or in different lobes of the same lung. The five-year survival rates, calculated by the actuarial method, were: 33.89%, 12.74%, 11.11% and 0.00% for P1, P2, P3 and P4 respectively. The differences between P1 and the rest and between P4 and the rest were statistically significant but not the difference between P2 and P3.
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