Synthesis and characterization of cyclohexane-1R,2R-diamine-based Pt(iv) dicarboxylato anticancer prodrugs: their selective activity against human colon cancer cell lines.

Three pairs of asymmetric dicarboxylato derivatives based on the cisplatin and oxaliplatin-like skeletons have been synthesized de novo or re-synthesized. The axial ligands consist of one medium-chain fatty acid (MCFA), namely clofibrate (i.e. 2-(p-chlorophenoxy)-2-methylpropionic acid, CA), heptanoate (HA) or octanoate (OA), respectively, and an inactive acetato ligand that imparts acceptable water solubility to such conjugates. Stability tests provided evidence for the partial formation of two hydrolyzed products, corresponding to two monoaqua diastereomers derived from the substitution of an equatorial chlorido ligand with a water molecule. The complexes have been tested on three different colon cancer cell lines having different histological history, and also on the cisplatin-sensitive A2780 ovarian cancer cell line for comparison. This allowed the evaluation not only of the increase in activity on passing from Pt(ii) to Pt(iv) derivatives, but also the selectivity towards colon cancer cells brought about by the cyclohexane-1R,2R-diamine carrier ligand.

Cisplatin and valproate released from the bifunctional [Pt(IV)Cl2(NH3)2(valproato)2] antitumor prodrug or from liposome formulations: who does what?

The cisplatin-sensitive human ovarian cancer cells A2780 have been challenged with cationic liposomes containing the single drug cisplatin or valproate or their combination with an approximate 1 : 2 molar ratio, i.e. the same ratio present in preformed (OC-6-33)-diamminedichloridobis(valproato)platinum(iv), that releases such metabolites by intracellular Pt(iv) → Pt(ii) reduction. The results of this comparison confirm that valproate barely penetrates cells unless it is transported by liposomes or it is coordinated to a lipophilic Pt(iv) assembly. The two drugs have a synergistic action, cisplatin being the more potent antiproliferative agent. Even if the preformed (OC-6-33)-diamminedichloridobis(valproato)platinum(iv) releases cisplatin and valproate in the same amount as the liposome formulation, the Pt(iv) derivative is more active. This important feature, common to all Pt(iv) complexes having very lipophilic carboxylates, is attributable to their propensity to remain in cells and to continuously bind DNA, unlike cisplatin that is partially removed from cells by efficient efflux pathways.

Functionalized nonporous silica nanoparticles as carriers for Pt(iv) anticancer prodrugs.

Nonporous silica nanoparticles (SNPs) with an external shell containing primary amino groups were proposed as potential delivery systems for Pt(iv) antitumor prodrugs. Spherical SNPs containing two different external arms, i.e. 3-aminopropyl and N-(6-aminohexyl)aminomethylene, of around 125 nm hydrodynamic diameter were loaded with two different cisplatin-based Pt(iv) complexes, namely (OC-6-44)-diamminedichloridoethoxidosuccinatoplatinum(iv) and (OC-6-44)-diamminedichloridoacetylamidosuccinatoplatinum(iv), through the formation of amide bonds between the pendant amino groups on SNPs and the free carboxylic group of the complexes. In the presence of the N-(6-aminohexyl)aminomethylene arm, the Pt(iv)-SNP conjugates showed a negligible (unwanted) Pt release by hydrolysis, whereas in the presence of ascorbic acid the reduction of Pt(iv) → Pt(ii) caused the substantial release of the active metabolite cisplatin. Conjugate Pt(iv)-SNP exhibited better antiproliferative activity on the Pt-sensitive A2780 human ovarian cancer cell line than the parent cisplatin and their free Pt(iv) precursors, due to their more efficient cellular uptake, likely by endocytosis.

Protective effect of metallothioneins against oxidative stress evaluated on wild type and MT-null cell lines by means of flow cytometry.

It is generally accepted that metallothioneins (MTs) are devoted to the regulation of the metabolism of essential trace metals and to chelation of toxic metals. Nowadays, there is increasing evidence that MTs also act as free radical scavengers. We employed wild type mouse embryo fibroblast cell line, GKA1, and its MT-null variant, GKA2, in order to correlate the presence of MTs to the sensitivity of cells to reactive oxygen species (ROS), spontaneously generated by the aerobic cellular metabolism, or chemically induced by hydrogen peroxide. The absence of MTs in GKA2 cells was unambiguously correlated to higher sensitivity to ROS attack, as evaluated by detection and quantification of 8-oxo-2'-deoxyguanosine (8-oxo-G), the first product of oxidative attack to DNA, using Fluorescence-Activated Cell Sorter (FACS). When compared to MT-null cell line, the wild type cells (GKA1) were less sensitive to ROS attack. In GKA1 cells, MT biosynthesis is readily induced by Cd2+ treatment, and such an induction caused a further decrease in sensitivity to ROS injury. On the contrary, the MT-null cells (GKA2) expressed no detectable metallothioneins either constitutively, or after heavy metal pretreatment. Indeed, in GKA2 cell line, pretreatment with Cd2+ did not reduce but even enhanced the oxidative stress.

Effect of metal-based anticancer drugs on wild type and metallothionein null cell lines.

Metallothioneins (MT) are ubiquitous low-molecular-weight metal-binding intracellular proteins. We used wild type mouse embryo fibroblasts, GKA1, and its MT-null variant, named GKA2, in order to correlate the presence of MT to the response to a number of different antitumor drugs with different mechanisms of action. We studied sensitivity of GKA1 and GKA2 cells to metal-based compounds having alkylating property, or able to generate reactive oxygen species (ROS); as well as to drugs acting with different mechanisms. The absence of MT in GKA2 cells was correlated to higher sensitivity to the metal-based drugs compared to that of GKA1. No marked differences in sensitivity of two cell lines against gemcitabine, taxol, and vinblastine were observed. No significant change in sensitivity of either GKA1 or GKA2 cells to these non-alkylating drugs was seen after heavy metal pretreatments. In GKA1 cells, MT biosynthesis was induced by copper and cadmium but not by zinc treatment under the conditions of these experiments. Induction of MT was directly proportional to decrease in sensitivity of GKA1 cells to the compounds used in this experiment. In contrast to GKA1 cells, the MT-null cells (GKA2) expressed no detectable metallothionein either constitutively or after treatment with zinc, copper, or cadmium. Nonetheless, heavy metal pretreatment of GKA2 cells did not cause any change in their sensitivity.

Use of heavy-metal clusters in the design of N-succinimidyl ester acylation reagents for side-chain-specific labeling of proteins.

New heavy transition metal carbonyl markers for protein labeling, containing an "Mn(CO)11" (M = Ru, Os, n = 3; M = Ir, n = 4) moiety, were prepared by reaction of "lightly stabilized" clusters with an N-succinimidyl ester functionalized phosphine, namely N-succinimidyl 3-diphenylphosphine-propionate (DPPS). The reaction of Os3(CO)11(DPPS) with the model amino acid beta-alanine was performed and led to the expected amide. From the reaction of Mn(CO)11(DPPS) with bovine serum albumin (BSA) in mixed organic/aqueous medium, conjugates bearing a fairly high number of metal carbonyl fragments were obtained, thus demonstrating the usefulness of this class of reagents for the selective and covalent graft of heavy metal clusters to side chain of proteins.

Supernatant of human umbilical vein endothelial cell culture can favour in vivo neutropoiesis.

Umbilical vein endothelial cells are known to be able to produce interleukins and colony stimulating factors. In the present work supernatant of human umbilical vein endothelial cell culture have been administered to neoplastic patients treated with chemotherapy to reduce the iatrogenic inhibition of hemopoiesis. While no undesired effect could be observed, neutrophil count was favourably influenced by endothelial cell supernatant administration. Such data can be considered useful in order to reduce collateral effect of antineoplastic therapy.

Comparison of intravenously administered doxofylline and placebo for the treatment of severe acute airways obstruction.

This double-blind, randomized, placebo-controlled study investigated the therapeutic effects of a single dose of doxofylline, a methylxanthine derivative, in 10 patients aged 26-79 years. All patients had acute exacerbation of chronic obstructive airways disease partially reversible with salbutamol inhaler. Doxofylline was administered intravenously at a dose of 200 mg over 15 min on two different occasions separated by at least 24 h. Doxofylline increased forced expiratory volume in the first second of expiration compared with baseline as follows: +20% after 2 h (P less than 0.01); +31% after 4 h (P less than 0.01); and +13% after 6 h (NS). Changes produced by placebo at these times were -4.4%, -14% and -5% (all NS). The average differences between the groups were significant at all observation times. At the end of the observation period eight out of 10 patients given doxofylline and one out of 10 patients given placebo had improved clinically according to the patients' own opinion. Clinical tolerability of doxofylline proved to be good since no signs of local or general side-effects were observed in any of the patients treated.

[Double-blind study of the bronchodilating action of the aminophylline-clenbuterol combination in asthmatic patients]. / Studio in doppio cieco dell'attività broncodilatatrice dell'associazione aminofillina-clenbuterolo nei pazienti asmatici.

The results obtained with the administration of aminophylline and clenbuterol either separately or in association, to a group of patients with chronic obstructive bronchopneumopathies are reported. The two drugs had a more or less identical broncho-dilatory effect with the beta 2-stimulant acting earlier but for a shorter time. The simultaneous administration of both drugs gave distinctly better results.

[Ultrastructure of the pulmonary alveolus. Correlations with the endoalveolar tensioactive system]. / Ultrastruttura dell'alveolo polmonare. Correlazioni con il sistema tensioattivo endoalveolare.

The knowledge of chemical structure and physiologic role of endoalveolar tensioactive system are a progress of the last ten years. The authors deal with the origin, fate and relationships with pulmonary surfactant metabolism of alveolar cells. Morphology and functions of alveolar-capillary membrane, type I and II cells, bronchiolar non-ciliated Clara cells and alveolar macrophages have been outlined. Lamellar bodies, alveolar type II cells intracitoplasmatic inclusions were particularly considered, as well as tubular myeline structures.

[The electrocardiogram and arterial hypertension in primary hyperparathyroidism]. / Elettrocardiogramma ed ipertensione arteriosa nell'iperparatiroidismo primitivo.

Cardiovascular conditions of 27 patients with primary hyperparathyroidism have been examinated. Hypertension has been found to be the only alteration significantly present (33,33% of patients), while heart disease are uncommon. Hypertension is often present without concomitant disease of the kidney. Blood pressure became normal in only one case over nine (11,11%) after parathyroidectomy.

Radioisotopic labelling of endoalveolar surface-active phospholipidic fractions from rabbit pulmonary lavage.

A simple method of detecting endoalveolar tensioactive system fractions employing intravenously injected 131I-triolein has been devised. The tracer has been administered to 7 adult rabbit groups then sacrificed at different time intervals after the injection. Endoalveolar tensioactive system lipidic fractions collected by pulmonary lavage have been separated with thin-layer chromatography and their radioactivity evaluated by scanning plates. Endoalveolar tensioactive system fractions containing considerable amounts of C 18 fatty acids have been selectively labelled.