Adapting a transforming growth factor beta-related tumor protection strategy to enhance antitumor immunity

Transforming growth factor beta (TGF-beta), a pleiotropic cytokine that regulates cell growth and differentiation, is secreted by many human tumors and markedly inhibits tumor-specific cellular immunity. Tumors can avoid the differentiating and apoptotic effects of TGF-beta by expressing a nonfunctional TGF-beta receptor. We have determined whether this immune evasion strategy can be manipulated to shield tumor-specific cytotoxic T lymphocytes (CTLs) from the inhibitory effects of tumor-derived TGF-beta. As our model we used Epstein-Barr virus (EBV)-specific CTLs that are infused as treatment for EBV-positive Hodgkin disease but that are vulnerable to the TGF-beta produced by this tumor. CTLs were transduced with a retrovirus vector expressing the dominant-negative TGF-beta type II receptor HATGF-betaRII-Deltacyt. HATGF-betaRII-Deltacyt- but not green fluorescence protein (eGFP)-transduced CTLs was resistant to the antiproliferative and anticytotoxic effects of exogenous TGF-beta. Additionally, receptor-transduced cells continued to secrete cytokines in response to antigenic stimulation. TGF-beta receptor ligation results in phosphorylation of Smad2, and this pathway was disrupted in HATGF-betaRII-Deltacyt-transduced CTLs, confirming blockade of the signal transduction pathway. Long-term expression of TGF-betaRII-Deltacyt did not affect CTL function, phenotype, or growth characteristics. Tumor-specific CTLs expressing HATGF-betaRII-Deltacyt should have a selective functional and survival advantage over unmodified CTLs in the presence of TGF-beta-secreting tumors and may be of value in treatment of these diseases.     

Characterization of the levels of expression of retinoic acid receptors,galectin-3, macrophage migration inhibiting factor,and p53 in 51 adamantinomatous craniopharyngiomas

OBJECT: Craniopharyngiomas are histopathologically defined as benign tumors that can behave very aggressively at the clinical level. They can originate from different types of embryonal epithelial tissue in which correct spatiotemporal regulation has been disrupted at the effector production level. The goal of this study was to determine the efficacy of using selected biological markers to distinguish between recurring and nonrecurring craniopharyngiomas. METHODS: The authors used computer-assisted microscopy to determine quantitatively the immunohistochemical levels of expression of selected markers, including retinoic acid receptors (RARs), as response elements to retinoic acid in a series of 51 adamantinomatous craniopharyngiomas. These tumors may also originate as the result of physiological defects in the apoptosis-mediated elimination of embryological remnants of epithelial tissue. Galectin-3, p53, and the macrophage migration inhibiting factor (MIF) are known to play crucial roles in these processes. The authors quantitatively determined the levels of expression of these substances in this series of 51 craniopharyngiomas. The data show that all craniopharyngiomas were immunoreactive for RARalpha, whereas their immunoreactivity for RARbeta and RARgamma varied dramatically from one case to another. Craniopharyngiomas with low levels of RARbeta and high levels of RARgamma are more likely to recur than those with higher levels of RARbeta and lower levels of RARgamma. Rapidly recurring craniopharyngiomas also show significantly lower levels of expression of galectin-3 and MIF than nonrecurring or slowly recurring cases. Few tumors exhibited p53 immunopositivity. CONCLUSIONS: The data indicate that even in the so-called adamantinomatous group of craniopharyngiomas, several subgroups with different clinical behavior patterns can be identified on the basis of differentiation markers relating mainly to the presence or absence of RARbeta and RARgamma.     

Biomolecules linked to transition metal complexes--new chances for chemotherapy

From the synthetic point of view the fast developing fields of medicine and biology offer new opportunities for the design of very effective drugs with high selectivity. Especially in the field of anticancer therapy many efforts have been made to deliver drugs to specific tissues. Sugar substituted porphyrin compounds, bile acid conjugates, and pH-sensitive immunoliposomes are only some examples. Although there are many different approaches to exploit biomolecules as shuttles only a start has been made. Since the targeting of a drug is a very complex process, a successful design of a new compound has to consider chemical as well as biological aspects and requires a multidisciplinary cooperation with physicians and biologists. Three interesting concepts are evaluated exemplarily: antibodies, molecules with binding affinity to hormone receptors, and bile acids. The main issues are: selection of the drug and the carrier, ways of linking the pharmacological active compound to the biomolecule, the optimal way of linking the drug to the spacer, and cytotoxicity, apoptosis, and drug resistance.     

Effects of sildenafil (viagra) on human myocardial contractility,in vitro arrhythmias,and tension of internal mammaria arteries and saphenous veins

Sildenafil (Viagra) has been proved effective in the therapy for erectile dysfunction. Cardiovascular adverse effects are a matter of continuous debate. The aim of the study was to investigate effects of sildenafil on isolated human cardiovascular tissue directly. Isometric force of contraction was determined in isolated, electrically stimulated (1 Hz, 37 degrees C) human right atrial and left ventricular muscle strips. Vascular tension was determined in rings of human internal mammaria arteries and saphenous veins. Sildenafil (0.0001-10 microM) neither in human atrium (n = 12) nor in failing (n = 8) or nonfailing (n = 5) ventricle exerted a significant inotropic response. Furthermore, no effect on isoprenaline-elicited arrhythmias was observed. Neither addition of isoprenaline (0.1 microM) nor addition of the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP) (100 microM) affected myocardial contractility in the presence of sildenafil (10 microM). In precontracted arteries and veins, addition of sildenafil (0.1-10 microM) led to pronounced vasorelaxation (maximal 35.5 +/- 2.2% and 45.6 +/- 6.3%, respectively, in the presence of 10 microM sildenafil). In the presence of SNAP (0.03 microM), this effect was markedly increased in arteries (72.4 +/- 10.1%, n = 4, P < 0.02) as well as in veins (73.5 +/- 6.3%, n = 6, P < 0.02). Sildenafil exerts potent vasodilatory actions but has no direct influence on human myocardial contractility or proarrhythmic effects in vitro.     

Atypical adenomatous hyperplasia of lung: its incidence and analysis of clinical, glycohistochemical and structural features including newly defined growth regulators and vascularization

BACKGROUND: Adenomatous hyperplasia of the peripheral lung has been suggested to be a preneoplastic lesion leading to peripherally localized lung carcinomas. The paucity of data about cellular and vascular characteristics of this lesion in comparison to normal lung prompted this investigation. MATERIAL AND METHODS: We describe results of two investigations comprising 75 cases and 70 cases, respectively, with atypical adenomatous hyperplasia (AAH) of the lung, respectively: (a) a prospective study part with thorough analysis of surgical lung specimens (lobes and lungs) for light microscopical detection of the lesion; and (b) a retrospective study part with immuno- and lectin histochemical analysis of AAH and non-neoplastic lung parenchyma monitoring expression of growth-related markers and changes in vascularization patterns. Sections of the individual cases were examined by an image-analyzing system including automated measurement of staining intensities and structure analysis. RESULTS: The prospective study part revealed an incidence of AAH in 2/31 cases with squamous cell carcinoma and in 5/32 cases with adenocarcinomas. No relation to pT- or pN stages was detectable, high grade AAHs were seen to be close to the tumor lesions (<2 cm distance) and those with low grade at greater distances. Statistically significantly increased levels of expression of anti-apoptotic bcl-2, macrophage migration inhibitory factor (MIF) capable to suppress p53 activities, heparin-binding lectin, interleukin-2, galectin-1 and of binding sites for the endogenous lectins galectins-1, -3 and -7 were determined. In addition, alveolar-lining cells, which express these markers, formed spatial clusters, which harbor different levels of structural entropy. AAH displayed an increased level of vascularization characterized by regular size and increased number of newly formed vessels. INTERPRETATION: The prospective and retrospective study parts point to a close association of AAH with peripherally localized adenocarcinoma of the lung. AAH is characterized by pronounced alteration of expression of several growth-related markers and probably non-reversible changes in vascularization.     

In vitro studies indicate that miquelianin (quercetin 3-O-beta-D-glucuronopyranoside) is able to reach the CNS from the small intestine

Miquelianin (quercetin 3-O-beta-D-glucuronopyranoside) is one of the flavonoids of St. John's wort (Hypericum perforatum L.) whose antidepressant activity has been shown by the forced swimming test, an in vivo pharmacological model with rats. However, nothing is known about its ability to reach the CNS after oral administration. We examined the pathway of miquelianin from the small intestine to the central nervous system using three in vitro membrane barrier cell systems. In the Caco-2 cell line, miquelianin showed a higher uptake (1.93 +/- 0.9 pmol x min(-1) x cm(-2)) than hyperoside (quercetin 3-O-beta-D-galactopyranoside; 0.55 +/- 0.18 pmol x min(-1) x cm(-2)) and quercitrin (quercetin 3-O-alpha-L-rhamnopyranoside; 0.22 +/- 0.08 pmol x min(-1) x cm(-2)). The permeability coefficient of miquelianin (Pc = 0.4 +/- 0.19 x 10(-6) cm/sec) was in the range of orally available drugs assuming sufficient absorption from the small intestine. Uptake and permeability of the examined compounds was increased by the MRP-2 inhibitor MK-571 indicating a backwards transport by this membrane protein. Porcine cell cultures of brain capillary endothelial cells were used as a model of the blood-brain barrier (bbb) and epithelial cells of the plexus chorioidei as a model of the blood-CSF barrier (bcb). Results indicate no active transport in one direction. Although moderate, the permeability coefficients (bbb: Pc = 1.34 +/- 0.05 x 10(-6) cm/sec; bcb: Pc = 2.0 +/- 0.33 x 10(-6) cm/sec) indicate the ability of miquelianin to cross both barriers to finally reach the CNS.     

Bedside Percutaneous Tracheostomy: Clinical Comparison of Griggs and Fantoni Techniques

Elective tracheostomy is widely considered the preferred airway management of patients on long-term ventilation. In addition to open tracheostomy, a number of percutaneous procedures have been introduced during the last two decades, among them techniques according to Griggs (guidewire dilating forceps, or GWDF) and to Fantoni (translaryngeal tracheostomy, or TLT). The aim of the study was to evaluate these two techniques in terms of perioperative complications, risks, and benefits in critically ill patients. A series of 100 critically ill adult patients on long-term ventilation underwent elective percutaneous tracheostomy, either according to the Griggs (n= 50) or Fantoni (n= 50) technique. Tracheostomy was performed under general anesthesia at the patient's bedside. The mean (±SD) operating times were short, 9.2 ± 3.9 minutes (TLT) and 4.8 ± 3.7 minutes (GWDF) on average. Perioperative complications were noted in 4% of patients during either TLT or GWDF and included massive bleeding, mediastinal emphysema, posterior tracheal wall injury, and pretracheal placement of the tracheostomy tube. With regard to oxygenation, pre- and postoperative arterial oxygen tension divided by the fraction of inspired oxygen (PaO₂/FiO₂) ratios did not vary significantly, and no perioperative hypoxia was noted regardless of the technique used. We conclude that both TLT and GWDF represent attractive, safe alternatives to conventional tracheostomy or other percutaneous procedures if carefully performed by experienced physicians and under bronchoscopic control.     

CT-Fluoroscopy: Tool or Gimmick?

Recent advances in CT scanner technology and computer hardware have led to the development of CT fluoroscopy (CTF), which allows real-time acquisition and display of cross-sectional images (with a rate of up to 8 frames per second). Since the introduction of the first CT fluoroscopy scanner in 1993, a variety of these scanners have been installed world-wide and many reports on the clinical use of this device have appeared recently. However, use of this new technology for the guidance of interventional radiologic procedures, such as percutaneous biopsy and percutaneous drainage, is not uniformly advocated by interventional radiologists. Concerns have been reported regarding radiation exposure and outcome of the procedures when compared with sequential CT guidance or other alternative guiding modalities. This article is intended to present an overview of CTF technology, to summarize the results of published papers on various interventional applications and to reflect on its specific advantages and disadvantages.