p53-dependent ICAM-1 overexpression in senescent human cells identified in atherosclerotic lesions.

Most normal somatic cells enter a state called replicative senescence after a certain number of divisions, characterized by irreversible growth arrest. Moreover, they express a pronounced inflammatory phenotype that could contribute to the aging process and the development of age-related pathologies. Among the molecules involved in the inflammatory response that are overexpressed in senescent cells and aged tissues is intercellular adhesion molecule-1 (ICAM-1). Furthermore, ICAM-1 is overexpressed in atherosclerosis, an age-related, chronic inflammatory disease. We have recently reported that the transcriptional activator p53 can trigger ICAM-1 expression in an nuclear factor-kappa B (NF-kappaB)-independent manner (Gorgoulis et al, EMBO J. 2003; 22: 1567-1578). As p53 exhibits an increased transcriptional activity in senescent cells, we investigated whether p53 activation is responsible for the senescence-associated ICAM-1 overexpression. To this end, we used two model systems of cellular senescence: (a) human fibroblasts and (b) conditionally immortalized human vascular smooth muscle cells. Here, we present evidence from both cell systems to support a p53-mediated ICAM-1 overexpression in senescent cells that is independent of NF-kappaB. We also demonstrate in atherosclerotic lesions the presence of cells coexpressing activated p53, ICAM-1, and stained with the senescence-associated beta-galactosidase, a biomarker of replicative senescence. Collectively, our data suggest a direct functional link between p53 and ICAM-1 in senescence and age-related disorders.

AIDS-related cardiac tamponade: is surgical drainage justified?

In order to evaluate the usefulness of surgical drainage in the treatment of patients with acquired immunodeficiency syndrome (AIDS)-related cardiac tamponade, we reviewed our experience with subxiphoid pericardiostomy on 5 consequent such patients. One patient died in the immediate postoperative period and the remaining 4 died within 21 weeks after the operation. Similar results have been reported by other authors who found that surgical drainage has no diagnostic or therapeutic benefit over pericardiocentesis in this particular group of patients. Based on our limited experience and the data of the literature, we feel that surgical drainage cannot be justified as the primary method of treatment of AIDS-related cardiac tamponade.

Transcription factor E2F-1 acts as a growth-promoting factor and is associated with adverse prognosis in non-small cell lung carcinomas.

Numerous upstream stimulatory and inhibitory signals converge to the pRb/E2F pathway, which governs cell-cycle progression, but the information concerning alterations of E2F-1 in primary malignancies is very limited. Several in vitro studies report that E2F-1 can act either as an oncoprotein or as a tumour suppressor protein. In view of this dichotomy in its functions and its critical role in cell cycle control, this study examined the following four aspects of E2F-1 in a panel of 87 non-small cell lung carcinomas (NSCLCs), previously analysed for defects in the pRb-p53-MDM2 network: firstly, the status of E2F-1 at the protein, mRNA and DNA levels; secondly, its relationship with the kinetic parameters and genomic instability of the tumours; thirdly, its association with the status of its transcriptional co-activator CBP, downstream target PCNA and main cell cycle regulatory and E2F-1-interacting molecules pRb, p53 and MDM2; and fourthly, its impact on clinical outcome. The protein levels of E2F-1 and its co-activator CBP were significantly higher in the tumour area than in the corresponding normal epithelium (p<0.001). E2F-1 overexpression was associated with increased E2F-1 mRNA levels in 82% of the cases examined. The latter finding, along with the low frequency of E2F-1 gene amplification observed (9%), suggests that the main mechanism of E2F-1 protein overexpression in NSCLCs is deregulation at the transcriptional level. Mutational analysis revealed only one sample with asomatic mutation at codon 371 (Glu-->Asp) and one carrying a polymorphism at codon 393 (Gly-->Ser). Carcinomas with increased E2F-1 positivity demonstrated a significant increase in their growth indexes (r=0.402, p=0.001) and were associated with adverse prognosis (p=0.033 by Cox regression analysis). The main determinant of the positive association with growth was the parallel increase between E2F-1 staining and proliferation (r=0.746, p<0.001), whereas apoptosis was not influenced by the status of E2F-1. Moreover, correlation with the status of the pRb-p53-MDM2 network showed that the cases with aberrant pRb expression displayed significantly higher E2F-1 indexes (p=0.033), while a similar association was noticed in the group of carcinomas with deregulation of the p53-MDM2 feedback loop. In conclusion, the results suggest that E2F-1 overexpression may contribute to the development of NSCLCs by promoting proliferation and provide evidence that this role is further enhanced in a genetic background with deregulated pRb-p53-MDM2 circuitry.

Growth index is independent of microvessel density in non-small-cell lung carcinomas.

Induction of angiogenesis is essential for carcinogenesis and facilitates the processes of tumor development and metastasis. Vascular endothelial growth factor (VEGF) is an important angiogenic regulator under physiologic and pathologic conditions. To elucidate the role of angiogenesis in malignant growth, we evaluated angiogenesis and VEGF expression in a panel of 68 non-small-cell lung carcinomas (NSCLCs) and examined their relation with the kinetic parameters, ploidy, and p53 protein status, which have been analyzed previously. Angiogenesis was estimated as microvascular density (MVD) of the tumor area by CD31 immunodetection. Expression of VEGF was also immunohistochemically evaluated. All possible associations were assessed through a series of statistical methods. The mean MVD value was 39 microvessels/mm(2), and high VEGF immunoreactivity was observed in all specimens, with a mean percentage of positive cells of 73%. The relation between MVD and VEGF expression was not statistically significant (P = 0.065). No association was observed between MVD or VEGF levels with the proliferation index, apoptotic index, tumor ploidy status, p53 expression, and overall survival. We conclude that in a subset of NSCLCs, angiogenesis may be associated with VEGF, but other factors also participate in this process. Angiogenesis and growth (proliferation and apoptosis) are independent and probably differentially operated procedures, with only growth partially controlled by p53 protein expression.

Detection of acute postoperative mediastinitis in mice using (99m)Tc-liposomes.

RATIONALE AND OBJECTIVES: To evaluate the usefulness of size-modified (99m)Tc-labeled liposomes for the detection of acute postoperative mediastinitis in a mouse model. METHODS: Fourteen mice underwent low-neck collar incision and had sterile abscesses induced in mediastinum with turpentine. Ten of these animals were injected intravenously with anionic liposomes of 516 +/- 20 nm containing poly(ethylene)glycol labeled with (99m)Tc; the remaining four mice were injected with (67)Ga citrate and used as positive controls. In addition, eight mice either underwent the same surgical procedure but without turpentine (n = 4) or were not operated (n = 4). These were used as negative controls. Therefore, scintigraphy using (99m)Tc-liposomes was performed in eighteen and (67)Ga citrate in four mice. Target area of interest was outlined, and target to background count density ratio and percentage-injected dose were measured. RESULTS: Significant accumulation of radiolabeled liposomes was observed at sites of inflammation within 1 hour in abscess-bearing animals. This correlated well with the findings of the lower quality (contrast) of (67)Ga images at 24 and 48 hours. The radiopharmaceutical did not significantly accumulate in the mediastinum of negative control animals. CONCLUSION: (99m)Tc-liposomes (size modified) may prove useful nonspecific agent for the early diagnosis of postoperative mediastinitis.

Prognostic factors in non-small cell lung carcinoma.

This review aims in presenting the established and putative prognostic markers in non-small cell lung carcinoma (NSCLC). We have focused on the molecular/genetic alterations accompanying the pathogenesis of this malignancy, which may derange the cellular response to external and internal stimuli. A variety of factors influencing cell cycle progression, programmed cell death, drug resistance and immune evasion seem to obtain a predictive--though sometimes argued--role. Taking into account that a great number of these factors develope "cross-talking" protein-complex networks, their combined evaluation is likely to contribute towards a more accurate prediction of the clinical outcome in NSCLC patients.

Selective in vitro labeling of white blood cells using 99mTc-labeled liposomes.

We describe a method by which endocytosis-based radiolabeling of WBC is achieved using 99mTc-liposomes of optimal size and charge, and of a composition that assures both in vitro (whole blood) and intracellular stability of the radiopharmaceutical. In our study, excellent in vitro stability of 99mTc-liposomes with 95% labeling efficiency was observed with >90% stability up to 6 h and a minimum of 85% after 24 h of incubation either in normal saline or serum. Total WBC labeling efficiency using 99mTc-liposomes determined by radio-thin layer chromatographic analysis was 30.6 +/- 2.21%, 20.89 +/- 1.31% for monocytes and 9.7 +/- 1.74% for polymorphonuclears. Negligible activity was bound to red blood cells. The procedure did not affect the cell viability and the separation of the free 99mTc-liposomes from the cells was done by centrifugation.