[Detection of micro-vascular density(MVD) and its clinical significance in lung cancer]

BACKGROUND

To study the relationship between MVD of lung cancer tissues and the pathophysiological characteristics and prognosis in patients with lung cancer.

METHODS

The MVD was detected in 114 lung cancer tissues, 30 benign pulmonary tissues by immunohistochemical staining (LSAB method).

RESULTS

MVD in lung cancer tissues (30.47+/-10.56) was significantly higher than that in benign pulmonary tissues (10.23+/-6.92)(P<0.01); The MVD was closely related to the size of primary cancer, lymph node status, P-TNM stages, grade of cell differentiation of lung cancer (P<0.01), but not to the histological classification and site of the cancer, and age, sex and smoking or not in the patients with lung cancer (P<0.05); The 5-year survival rate in patients (17.27%) with high MVD (>=30) was significantly lower than that in patients (52.74%) with low MVD (<30)(P<0.01); The survival time of patients with lung cancer was negatively related to MVD (r=-0.521,P<0.01); The results of multivariable COX model showed that the P-TNM and MVD were the most significant variables for predicting prognosis among the all related factors in lung cancer.

CONCLUSIONS

Increase of MVD may play an important role in the oncogenesis, development, metastasis of lung cancer and might be served as a tumor marker to evaluate the biological behavior of lung cancer. Detection of MVD might be helpful to predict prognosis and guide the postoperative multi-modality therapy in patients with lung cancer.

Green tea and its major components ameliorate immune dysfunction in mice bearing Lewis lung carcinoma and treated with the carcinogen NNK

The protective effects of tea and/or its components on dysfunction of immune functions during tumor growth and carcinogenesis in mice were studied using two experimental models: C57/BL6J mice transplanted with Lewis lung carcinoma (LLC) and Kunming mice treated with a single dose of 4-(methylnitrosamino-)-1-(3-pyridyl)-1-butanone (NNK). In C57/BL6J mice bearing LLC, the weight of the thymus decreased, the proportion of CD4(+)-positive T lymphocytes and the ratio of CD4+ to CD8+ decreased, luminol-enhanced chemiluminescence of white blood cells in peripheral blood stimulated by zymosan increased, and plaque-forming cells (PFC) decreased. However, in LLC-bearing mice given green tea as drinking water, all immune functions were improved, along with inhibition of tumor growth. In Kunming mice treated with NNK, during the four weeks of observation, their immunologic indicators, such as phagocytosis of macrophages in the abdominal cavity, luminol-enhanced chemiluminescence of white blood cells, plaque-forming cells, and delayed-type hypersensitivity, increased or decreased to various extents compared with normal controls. However, these changes were significantly prevented in the mice given green tea, mixed tea, or tea polyphenol as drinking water. In conclusion, tea and its components ameliorated immune dysfunction in mice bearing LLC or treated with the carcinogen NNK.

Murine mammary gland carcinogenesis is critically dependent on progesterone receptor function

To define the functional relevance of progesterone-initiated intracellular signaling in mammary gland tumorigenesis, the progesterone receptor knockout (PRKO) mouse model was used in the context of an established carcinogen-induced mammary tumorigenesis system. In carcinogen-treated, 7,12-dimethylbenz(a)anthracene (DMBA), pituitary-isografted mice, there was a marked reduction in mammary tumor incidence in PRKO mice as compared with isogenic wild types (WT). Mammary tumors arose in 12 (60%) of 20 WT mice compared with 3 (15%) of 20 PRKO mice by 44 weeks after the initial DMBA treatment. In the absence of a pituitary isograft, mammary tumors developed in 4 (20%) of 20 WT mice versus 4 (20%) of 20 PRKO mice by 47 weeks. At the time of carcinogen administration, the proliferative index of the pituitary-stimulated WT gland was at least 4-fold higher than similarly treated PRKO glands, supporting the importance of PR-mediated proliferative pathways in the genesis of this tumor type. Unlike the WT gland, the PRKO gland was unable to exhibit alveologenesis in response to pituitary isograft stimulation; thus, DMBA-initiated mammary tumors observed in the PRKO were assumed to be exclusively of ductal origin. Compared with previous tested strains, by 47 weeks, a higher incidence of DMBA-induced ovarian tumors was observed in this mouse strain: (a) 4 (20%) of 20 WT mice and 9 (45%) of 20 PRKO mice with a pituitary isograft; and (b) 10 (50%) of 20 WT mice and 10 (50%) of 20 PRKO mice without a pituitary isograft. Despite the host-strain's underlying propensity for DMBA-induced ovarian neoplasms, our studies underscore the specific importance of the PR (as distinct from the estrogen receptor) as a mandatory mediator for those intracellular signaling pathways that are essential for the initiation of the majority of murine mammary tumors induced by DMBA. Apart from providing strong support for progesterone's role in mammary gland tumorigenesis as well as furthering our fundamental understanding of breast cancer etiology, these studies may have implications for the routine use of progestins.

[Effects of green tea on growth inhibition and immune regulation of Lewis lung cancer in mice]

C57/BL6J mice were inoculated with Lewis lung cancer cells as an experimental model to study the effects of green tea on cancer prevention, inhibition of tumor growth and immune regulation in mice with tumor. Results showed that weight of thymus in C57/BL6J mice and its index declined, proportion of positive CD4 subgroup of T lymphocyte and ratio of CD4+, to CD8+ reduced, baseline chemilumi-nescence decreased in peripheral white blood cells, yeast zymosan stimulated chemiluminescence increased, and number of immunoglobulin M formation cells decreased. It indicated that green tea had obvious inhibition in Lewis lung cancer and protective effects, to various extent, on adverse changes of above indices.

Room-temperature fluorescence properties of the polynucleotide polydA.polydT

The room-temperature fluorescence spectrum of the non-alternating polynucleotide polydA.polydT is found to have its maximum at about 325 nm and, when exciting in the spectral region where both adenine (A) and thymine (T) absorb, to coincide with that obtained for excitation at 293 nm where thymine is selectively excited. The fluorescence anisotropy is found to be equal to 0.18 and independent of the excitation and emission wavelengths. These observations are consistent with: (i) emission stemming from T; and (ii) transfer of electronic energy from A to T being not efficient. These inferences are also supported by the observed dependence of the fluorescence quantum yield on the excitation wavelength.

Excited-state properties of the alternating polynucleotide poly(dA-dT).poly(dA-dT)

Measurements of the steady-state fluorescence spectrum and anisotropy, r, of the alternating polynucleotide poly(dA-dT).poly(dA-dT) were carried out in order to characterize its photophysical properties at room temperature. The shape of the fluorescence spectrum depends on the excitation wavelength, namely, the relative fluorescence intensity of the short-wavelength peak decreases for excitation at short wavelengths. When monitoring the emission at short wavelengths, r is 0.18 and independent of the excitation wavelength. When monitoring the emission at long wavelengths, however, r is very low, about 0.03. These results suggest that: (i) the short-wavelength emission stems from thymine; and (ii) the long-wavelength emission stems from an excited-state complex (excimer), with the same one being formed regardless of whether thymine or adenine is excited. The corresponding fluorescence spectra have been resolved. The occurrence of transfer of electronic energy is discussed.

Singlet-singlet energy transfer along the helix of a double-stranded nucleic acid at room temperature

An irreversible electronic energy trap has been formed in calf thymus DNA by methylating about 75% of its G bases at position N-7. This has allowed us to measure for the first time the efficiency of transfer of energy along the helix of a double-stranded nucleic acid at room temperature. It is found that about one out of every three photons absorbed by the other bases is trapped. We have also simulated the data with a stochastic model that uses the dipole-dipole interaction to calculate the efficiency of transfer. In order to approximate the experimental results, the model requires that: (i) the fluorescence quantum yield of T, C, and G in DNA be about 2 x 10(-3), which is about two orders of magnitude larger than the value of the fluorescence quantum yield reported for DNA; and (ii) the fluorescence quantum yield of A in DNA be negligibly small. Requirement (i) is consistent with energy transfer taking place before a very efficient fluorescence quenching process sets in, which could be formation of excited-state complexes (excimers) that do not fluoresce appreciably. Requirement (ii) implies a very short fluorescence lifetime for A, which is consistent with the reported absence of a significant number of photoproducts formed by A in DNA. The simulations find that, on the average, the excitation energy takes about 1.2 steps to reach the trap; that is to say, bases that are nearest and next nearest neighbors of the trap are, in effect, the only energy donors. Both intra- as well as interstrand energy transfer (the latter only for the C-trap base pair) make significant contributions. The value of the efficiency for pairwise base-base intrastrand transfer is about 60%, whereas those for base-trap intra- and interstand transfer are 90% and 80%, respectively. The corresponding values for the rate constant of transfer are 2 x 10(11), 1 x 10(12), and 4 x 10(11) s-1. Transfer is inefficient when A is the donor or the acceptor. In addition to the dipole-dipole term, the only other significant term in the expansion of the interaction potential is the dipole-quadrupole term which, however, makes only a small contribution to the overall transfer efficiency. The electron exchange interaction appears to be much less efficient than the coulombic interaction.