[Quality in dialysis]. / La qualità in dialisi.

BACKGROUND: Several clinical and laboratory dialysis parameters have been suggested by national and international guidelines. Our study aimed to evaluate a series of quality indicators in the dialytic treatment of a group of patients in our two dialytic centers. PATIENTS AND METHODS: In a population of 159 patients on renal replacement therapy (RDT) we performed a 1-yr prospective observational study, with common parameters to indicate cardiovascular pathologies (PAS, LVMI), calcium-phosphorous metabolism (Ca, PO 4 , Ca x PO 4 ), dialytic adequacy (Kt/V, URR%), nutritional status (nPCR, Alb, K), and anemia (hemoglobin (Hb)). For each parameter we evaluated the mean average with the standard deviation and the score percentages below and above the acceptable range (AR). RESULTS: The results demonstrated a substantial stability, with a gradual improvement, in dialytic adequacy, in anemic status and in PAS. The LVMI, calculated at the beginning and at the end of the period, did not demonstrate any significant changes. No significant changes were observed in the calcium-phosphorous metabolism parameters. Serum albumin and nPCR demonstrated the presence of malnutrition in 15-20% of patients. CONCLUSIONS: There was a more than adequate correlation between the target guidelines and that concerning the dialytic adequacy and the corrected anemic status. The improvement in parameters related to cardiovascular pathology, the risk of ectopic calcifications and malnutrition status, represented an achievable target.

Cytotoxics derived from distamycin A and congeners.

Distamycin A is an antibiotic, characterised by an oligopeptidic pyrrolocarbamoyl frame ending with an amidino moiety, which binds reversibly to DNA minor groove with high selectivity for TA-rich sequences and shows antiviral and antiprotozoal activity. Distamycin was used as DNA sequence selective vector of alkylating functions, leading to a substantial increase of cytotoxicity in comparison to that, very weak, of distamycin itself. The benzoyl nitrogen mustard derivative of desformyldistamycin, tallimustine, was selected as a candidate antineoplastic drug in view of its strong activity against a series of experimental tumors. Tallimustine, like distamycin, shows DNA selective binding to TA-rich sequences but its cytotoxicity is not associated with DNA strand breaks and interstrand crosslinking, at variance with classical phenyl nitrogen mustards. Tallimustine represents an important model for the design of new minor groove alkylating agents derived from distamycin and analogues, including the so-called lexitropsins, sequence-reading oligopeptides in which one or more N-methyl-pyrrole units of distamycin are replaced by imidazole or other rings. The structural features of the alkylating moieties and binding frames, the antitumor activities and the mechanism of action of most representative cytotoxics derived from distamycin and congeners are discussed. Some of these, recently reported, show an activity profile apparently superior to tallimustine. Finally, a concise survey of representative hybrid compounds in which known non-alkylating cytotoxic agents or their active moieties have been tethered to distamycin and congeners is presented and briefly discussed. These compounds witness the attention paid to this approach on the basis of the interest for the DNA binding features of distamycin A.

Synthesis, DNA-binding properties, and antitumor activity of novel distamycin derivatives.

A group of potential alkylating agents have been synthesized that are structurally related to the oligopeptide antiviral antibiotic distamycin. All derivatives form complexes with native calf-thymus DNA but compounds 2, 3, and 6 give rise to covalent adducts. Cytostatic activity against both human and murine tumor cell lines in vitro is displayed by the new compounds. Compounds 3 and 4 are active on melphalan-resistant L1210 leukemia in mice.

Synthesis and antitumor activity of new benzoheterocyclic derivatives of distamycin A.

The design, synthesis, and in vivo and in vitro antileukemic activity of a novel series of compounds (13-22 and 34), in which different benzoheterocyclic rings, bearing a nitrogen mustard or a benzoyl nitrogen mustard or an alpha-bromoacryloyl group as alkylating moieties, are tethered to a distamycin frame, are reported, and structure-activity relationships are discussed. The new derivatives were prepared by coupling nitrogen mustard-substituted, benzoyl nitrogen mustard-substituted, or alpha-bromoacryloyl-substituted benzoheterocyclic carboxylic acids 23-32 with desformyldistamycin (33) or in one case with its two-pyrrole analogue 35. With very few exceptions, the activities of compounds bearing the same alkylating moiety are slightly affected by the kind of the heteroatom present on the benzoheterocyclic ring. All novel compounds, with one exception, showed in vitro activity against L1210 murine leukemia cell line comparable to or better than that of tallimustine. The compounds in which the nitrogen mustard and the alpha-bromoacryloyl moieties are directly linked to benzoheterocyclic ring showed potent cytotoxic activities (IC(50) ranging from 2 to 14 nM), while benzoyl nitrogen mustard derivatives of benzoheterocycles showed reduced cytotoxic activities, and one compound (16) of this cluster was the sole derivative devoid of significant activity. Compound 18, a 5-nitrogen mustard N-methylindole derivative of distamycin, showed the best antileukemic activity in vivo, with a very long survival time (%T/C = 457), significantly increased in comparison to tallimustine (%T/C = 133), and was selected for further extensive evaluation. Arrested polymerase chain reaction and direct DNA fragmentation assays were performed for compound 18 and the structurally related compounds 13-17 and 19. The results obtained have shown that both alkylating groups and oligopeptide frames play a crucial role in the sequence selectivity of these compounds.

Synthesis and immunosuppressive activity of novel prodigiosin derivatives.

Prodigiosins (Ps) represent a family of naturally occurring red pigments characterized by a common pyrrolylpyrromethene skeleton. Some members of this family have been shown to possess interesting immunosuppressive properties exerted with a novel mechanism of action, different from that of currently used drugs. In fact, Ps inhibit phosphorylation and activation of JAK-3, a cytoplasmic tyrosine kinase associated with a cell surface receptor component called common gamma-chain, which is exclusive of all IL-2 cytokine family receptors. Blocking common gamma-chain transduction activity results in a potent and specific immunosuppressive activity. With respect to the interesting and unexploited immunomodulating properties of this family of compounds we initiated a medicinal chemistry program aimed at finding novel prodigiosin derivatives with improved immunosuppressive activity and lower toxicity. Utilizing an unprecedented and flexible way of assembling the prodigiosin frame, a number of new derivatives have been prepared and tested leading to the choice of 4-benzyloxy-5-[(5-undecyl-2H-pyrrol-2-ylidene)methyl]-2, 2'-bi-1H-pyrrole (PNU-156804, 16) as a lead immunosuppressant.

The effects of a benzoic acid mustard derivative of distamycin A (FCE 24517) and related minor groove-binding distamycin analogues on the activity of major groove-binding alkylating agents.

The distamycin derivative FCE 24517 is a potent antitumour agent. Efforts have been made towards elucidating the mechanism of action of this compound which, to date, have highlighted a high level of DNA sequence specificity for covalent adduct formation. Compared to classical alkylating agents, FCE 24517 forms very few covalent adducts with double-stranded DNA, and thus appears to be a weak alkylating agent. Examination of the effects of this minor groove-binding agent on the major groove of DNA have been facilitated by use of the alkylating agents mustine, melphalan, dabis maleate, quinacrine mustard and uracil mustard. Pretreatment of plasmid DNA with FCE 24517 followed by reaction with any one of these mustards gave rise to a marked abolition of N-7 guanine adduct formation, as assayed by Maxam and Gilbert sequencing gels. The smallest effect was seen for quinacrine mustard, whereas total abolition of N-7 guanine alkylation was seen with uracil mustard. Using related structural analogues of FCE 24517 in the same experiments, it was not possible to reproduce this effect, with very few exceptions. Some effects were seen when using distamycin A itself in these experiments, although these were marginal compared to those seen for FCE 24517. We were able to extrapolate our findings to a whole cell system using murine L-1210 leukaemia cells. Alkaline elution experiments showed that treatment of cultured cells with FCE 24517 followed by either mustine or uracil mustard caused a marked inhibition of DNA interstrand crosslink formation, compared to treatment with mustine or uracil mustard alone. The present study has demonstrated the marked effect that FCE 24517 has upon the reactivity of double-stranded DNA, an effect possibly separate from that of its alkylating function. This study has highlighted the complex nature of the DNA interactive compound FCE 24517 which possess potent and broad spectrum antitumour activity.

New sulfonated distamycin A derivatives with bFGF complexing activity.

Tumor-induced neoangiogenesis is an essential event for solid tumor growth. Therefore, a compound able to block angiogenesis-promoting factors could have antitumor activity. The polysulfonated naphthylurea suramin is hypothesized to have this mode of action. A series of sulfonated distamycin A derivatives have been synthesized with the objective of identifying novel compounds able to complex basic fibroblastic growth factor (bFGF) and other factors involved in tumour angiogenesis, and consequently to block the angiogenic process. These new compounds have been characterized for their ability to inhibit bFGF binding, in vivo bFGF-induced angiogenesis and neovascularization of the chorioallantoic membrane, in comparison with suramin. The two most active compounds, FCE 26644 [7,7'-(carbonyl-bis(imino-N-methyl-4,2-pyrrolecarbonyl-imino(N-met hyl-4,2- pyrrole)carbonylimino))-bis(1,3-naphthalenedisulfonic acid)] and FCE 27164 [7,7'-(carbonyl-bis(imino-N-methyl-4,2-pyrrolecarbonyl-imino(N-met hyl-4,2- pyrrole) carbonylimino)-bis (1,3,5-naphthalenetrisulfonic acid)] have been selected for extended evaluation. Both compounds are active in inhibiting platelet-derived growth factor beta (PDGF beta) and interleukin-1 beta binding. Two different assays have been performed to study their mode of action: the sequential binding assay on bFGF and PDGF receptors and the bFGF-induced tyrosine phosphorylation assay. The results of the two assays are in agreement and indicate that no activity is observed if FCE 26644, FCE 27164 and suramin are administered as pretreatment, when a direct interaction of the compounds with bFGF and PDGF receptors is required. Conversely, inhibitory activity is observed when the compounds are allowed to form complexes with the growth factors themselves.

In vitro activity of novel sulphonic derivatives of distamycin A.

The successful growth of tumors is dependent on the process of vascularization elicited by the tumor itself. As confirmed by many authors, there is a correlation between the presence of factors that stimulate tumor growth and angiogenesis. One of the approaches we have explored to control angiogenesis has been to synthesize compounds able to complex growth factors. A number of sulphonated derivatives of distamycin A were found active in inhibiting the binding of bFGF and PDGF beta on Swiss 3T3 cells with ID50 values ranging between 142-587 microM for bFGF and 28-79 microM for PDGF beta. The effect of these new derivatives in inhibiting angiogenesis was initially explored in the chorioallantoic membrane assay. It was observed that the selected compounds were active in this model system at the concentration of 350 nm/pellet. These new molecules present low or no cytotoxic activity on M5076 murine reticulosarcoma cells, the ID50 values being higher than 60 microM after 72 h continuous exposure in vitro.

In vivo activity of novel sulphonic derivatives of distamycin A.

Solid tumor growth can be modulated through inhibition of vascularization elicited by angiogenic factors. With the objective to complex these factors, new derivatives of distamycin A were synthesized and evaluated in vitro [1] and in vivo for their ability, after i.v. administration, to inhibit bFGF-induced vascularization and the growth of M5076 murine reticulosarcoma implanted i.m. The tested compounds were able to block angiogenesis with inhibition values ranging between 70-100%. Moreover, they were found to be capable of inducing tumor inhibition with values ranging between 40% and 95% at non-toxic doses.

Novel sulfonated and phosphonated analogs of distamycin which inhibit the replication of HIV.

A series of novel distamycin-related polyanionic compounds were compared for their anti-HIV activity. Several were highly potent inhibitors of HIV virus-induced cell killing and viral replication of a wide variety of laboratory isolates, as well as a monocytotropic virus and a clinical isolate in human peripheral blood lymphocytes. These compounds are structurally different from other sulfonic acid containing compounds reported to be potent inhibitors of the human immunodeficiency virus (HIV) in two respects: (1) they are structurally related to the non-toxic minor groove DNA binder distamycin; and (2) a number of them contain the aromatic phosphonic acid group. The compounds that were evaluated can be categorized into monomeric or dimeric ureido structural classes incorporating the bisamido-N-methylpyrrolenaphthalene-sulfonic acid group, with differences in the number and position of the sulfonic acids on the naphthalene rings. Broader structure-activity studies were made possible through the synthesis and evaluation of the compounds containing only a single N-methylpyrrole unit, those incorporating the N-methylpyrazole structure, and compounds having the isosteric phosphonic acid group substituted for the sulfonic acid group. One of the most potent of the inhibitors was 2,2'[4,4'[[aminocarbonyl]amino]bis[N,4'-di[pyrrole-2-carboxamide- 1,1'-dimethyl]]-4,6,8 naphthalenetrisulfonic acid] hexasodium salt, NSC 651015. This compound, the phosphonic acid analog NSC 662162, and the monomeric compound NSC 651018 were studied to determine the mechanism of their inhibitory activity. Mechanistic studies revealed that inhibition was due to the disruption of virus attachment to CD(4+)-susceptible cells and a further restraint on fusion of virus and cell membranes. The relative tolerance of these compounds in mice suggests that sufficient antiviral concentrations could be reached in vivo and thus may prove valuable in the treatment of AIDS patients.

Antitumor activity of FCE 26644 a new growth-factor complexing molecule.

FCE 26644, or 7,7'-(carbonyl-bis[imino-N-methyl-4, 2 pyrrole carbonyl-imino(N-methyl-4,2-pyrrole)carbonyl-imino])-bis-(1,3- naphthalene)disulfonic acid, belongs to the newly synthesized class of sulfonated derivatives of distamycin A. FCE 26644 is a noncytotoxic molecule capable of inhibiting the binding of basic fibreblast growth factor (bFGF), platelet-derived growth factor (PDGF beta) and interleukin 1 (IL-7) to their receptors and to block bFGF-induced vascularization in vivo as well as neovascularization in the chorioallantoic membrane. FCE 26644 and suramin, a compound possessing the same terminal half-life (t1/2) in mice and, presumably, the same mode of action, inhibit the growth of solid murine tumors, M5076 reticulosarcoma, and MXT and S180 fibrosarcoma and are inactive against B16F10 melanoma. The activity of FCE 26644 was constantly observed at nontoxic doses, at variance with suramin. FCE 26644 was also found to maintain activity against M5076 resistant to cyclophosphamide and to be equally active against UV 2237 and UV 2237/ADR fibrosarcoma.

Synthesis, solvolytic stability and cytotoxicity of a modified derivative of CPzI, a pyrazole analog of the alkylation subunit of the antitumor agent CC-1065: effect of the nitrogen substitution on the functional reactivity.

The synthesis and the comparative preliminary biological evaluation of a new pyrazole analog (16) of the CC-1065 alkylating unit (CPI) are described. This new derivative showed low cytotoxicity against L1210 murine leukemia (IC50 3064 nM) with respect to reference compound, but contrarily to literature data, was found to be more stable to solvolysis than the natural derivative (+/-)-N-Boc-CPI (pH 3, t1/2 = 212 h vs. 37 h). The results of such investigation showed that alkylation of the pyrazole nitrogen caused a loss of cytotoxic activity in vitro against tumor cells. This experimental observation allowed us to confirm the importance of free N-H for the anticellular activity.

Synthesis, cytotoxicity and antitumor activity of some new simplified pyrazole analogs of the antitumor agent CC-1065. Effect of an hydrophobic group on antitumor activity.

Three simplified pyrazole analogs (7-9) of the antitumor agents CC-1065, were synthesized. In in vitro assays, against L1210 cell lines all derivatives showed a cytotoxicity in a pM range, values close to the natural target compound (+)-CC-1065. In in vivo tests, against disseminate L1210 leukemia cells, synthesized compounds showed a good potency (O.D. 300 micrograms/Kg) but no activity. These observations further validate the effect of the hydrophilic and/or hydrophobic characteristics of the substituents present on the molecules, confirming the relevance of this phenomena on in vivo activity. In fact in this case the increase of hydrophobic characteristics of the molecules produce the loss of activity, probably due to a worse bioavailability of the drugs in animals.

[Avascular jaw osteonecrosis in a hemodialysis patient treated with bisphosphonates]. / Osteonecrosi avascolare mandibolare in un paziente in trattamento emodialitico sostitutivo trattato con bifosfonati.

Bisphosphonates are molecules derived from pyrophosphates,but, unlike pyrophosphates, they are resistant to enzymatic hydrolysis. Bisphosphonates are used in the treatment of Paget's disease, cancer-related osteolysis, myeloma, primary hyperparathyroidism, and osteoporosis. In dialysis patients bisphosphonates may be used to reduce bone pain due to renal osteodystrophy. We describe the case of a 60-year-old woman with a history of breast cancer who had been on dialysis for 8 years. She had been receiving clodronic acid at 100 mg per week intravenously for the last 2 years. A year ago, the patient underwent surgical extraction of the lower right second molar. Her jaw pain increased in the following days. An orthopanthograph and a CT scan of the head showed osteolysis, and a surgical osteotomy was performed. Histological examination led to a diagnosis of avascular osteonecrosis of the jaw. Avascular osteonecrosis is typically described in the jaw. In this case, prolonged bisphosphonate treatment may have worsened the osteonecrosis.

Hypotensive effect in the rat after oral prostacyclin (PGI2).

PGI2 dose dependently lowers mean systemic arterial pressure in conscious normotensive and spontaneously hypertensive rats after oral administration. The ED30 was respectively 0.79 and 0.63 mg/kg. Heart rate was not significantly modified. The hypotensive effect appears to be due to PGI2 itself and not to its metabolite 6-keto-PGF1 alpha which, administered at 2 mg/kg p.o., did not modify blood pressure.

CCAAT-box binding protein NF-Y (CBF, CP1) recognizes the minor groove and distorts DNA.

The CCAAT box is one of the most common promoter elements. The evolutionarily conserved heteromeric factor NF-Y binds this sequence with high affinity and specificity. By comparing the methylation interference patterns of different sites, performing electrophoretic mobility shift assays (EMSA) with IC-substituted oligonucleotides and competition experiments with the minor groove binding (MGB) drugs distamicin A, tallimustine and Hoechst 33258 we show that NF-Y makes key minor groove interactions. Circular permutation assays on four CCAAT boxes, MHC Class II Ea, HSP70, epsilon-globin and MSV, indicate that NF-Y is able to distort the double helix by angles of 62-82 degrees, depending on the site used, and suggest that nucleotides flanking the CCAAT pentanucleotide influence the degree of bending.

Characterisation of a LoVo subline resistant to a benzoyl mustard derivative of distamycin A (FCE 24517).

Human colon adenocarcinoma cells (LoVo) resistant to the new antitumor agent FCE 24517 [benzoyl-mustard derivative of distamycin A] (LoVo/24517) are resistant to the selecting agent and related molecules as well as to vinblastine, with marginal or no resistance to other antitumour drugs. Treatment with verapamil, tamoxifen, nicergoline or cyclosporin A only partially restores the activity of FCE 24517 against LoVo/24517 cells. Such results suggest that resistance mechanisms possible specific for this class of compounds are operating.

Depression and excitation induced in mice by two geometric isomers of (+)13,14-didehydro-20-methyl-carboprostacyclin, FCE 22177 and FCE 22176. Comparison with effects on blood pressure and platelet aggregation.

Two geometric isomers of a stable derivative of PGI2 (13,14-didehydro-20-methyl-carbo PGI2), FCE 22177 (5E) and FCE 22176 (5Z), have been injected i.v. in mice (5-400 mcg/Kg) to investigate the effects at CNS level (Irwin's test). The synthetic mixture of the two isomers (5E:5Z = 7:3) was also tested. Isomers 5E and 5Z induced opposite effects: 5E (similar to PGI2) was depressive, 5Z induced stimulation. The mixture showed a strong depressive symptomatology. The two isomers and their mixture induced motor incoordination and impaired the performance of mice in the rotarod test (200 mcg/Kg i.v.). Mice were depressed after 5E and mixture; whilst 5Z induced excitation, in accordance with Irwin's test. 5E and 5Z showed analogous effects on mean blood pressure (hypotension) and heart rate (increase) in normotensive rats, but 5E was 7 times more active than 5Z. The two isomers showed analogous inhibitory effect on guinea-pig platelet aggregation in vitro, but 5E was 30 times more active than 5Z. In conclusion, the two geometric isomers have similar effects on blood pressure, heart rate and platelet aggregation, even if differing quantitatively. In contrast, 5E and 5Z have opposite effects at CNS level on motor function and behaviour. The data suggest the presence of two different sites of action for PGI2 in CNS (Ca2+- and adenylate cyclase-linked?). The two geometric isomers, 5E and 5Z, may be useful to study the PGI2 receptor sites in different tissues.

Pharmacological evaluation of 5-(Z,E)-13,14-didehydro-20-methyl-carboprostacyclin (FCE 22509).

FCE 22509, 5-(Z,E)-13,14-didehydro-20-methyl-carboprostacyclin, a chemically stable prostacyclin (PGI2) derivative, was 3.5 times more potent than PGI2 in relaxing bovine coronary artery in vitro; unlike PGI2, it did not contract bovine coronary vein and it antagonized PGI2-induced contractions of the coronary vein. In vitro smooth muscle (guinea pig ileum and trachea and rat stomach strip) was contracted to a lesser extent than with PGI2. FCE 22509 was about five times less potent than PGI2 in deaggregating platelet clumps formed on rabbit Achilles tendon bathed with heparinized cat blood (ED50 = 7.6 and 1.6 mcg/kg i.v. respectively). In the conscious normotensive and spontaneously hypertensive rat FCE 22509 lowered mean systemic arterial pressure (MSAP) (ED25 = 11.5 and 4.8 mcg/kg i.v.) to a lesser extent than PGI2 (ED25 = 2.1 and 2.34 mcg/kg i.v.) and increased heart rate but not dose-dependently. Orally administered, FCE 22509 likewise reduced MSAP though at high dosages (ED30 = 1.33 and 1.02 mg/kg in normotensive and hypertensive rats). Heart rate (HR) was raised after i.v. and oral treatment but not dose-dependently. In the open-chest anaesthetized dog, FCE 22509, compared with PGI2 at the same three doses, 0.2, 0.4 and 0.8 mcg/kg i.v., lowered MSAP but its hypotensive effect was less pronounced than that of PGI2. Like PGI2, FCE 22509 did not modify HR (though PGI2 showed a tendency to a decrease and FCE 22509 seemed to increase this cardiovascular function) and mean pulmonary arterial pressure (MPAP) and likewise significantly reduced myocardial contractile force. After infusion of PGI2 and FCE 22509 0.2 mcg/kg i.v. for 15 min in the open chest anaesthetized cat, the ex-vivo ADP-induced inhibition of platelet aggregation was the same for both compounds. Unlike PGI2, which reduced MSAP and MPAP, FCE 22509 had no significant lowering effect on MSAP and MPAP.

Comparative in vitro myelotoxicity of FCE 24517, a distamycin derivative, to human, canine and murine hematopoietic progenitor cells.

FCE 24517, a derivative of distamycin A, exhibits an unusual antitumor profile in experimental models. As part of its preclinical development, we evaluated the in vitro myelotoxicity of FCE 24517 to human, canine and murine hematopoietic cells. Marrow cells were exposed to the agent (2.7 x 10(-5) - 2.7 nM) for 4 h and then assayed in capillary (human) or Petri dish (canine, murine) clonal cultures. FCE 24517 inhibited myeloid (CFU-gm), erythroid (BFU-e, CFU-e) and megakaryocytic (CFU-meg) colony formation in a concentration-dependent manner. The progenitor cells were generally similar in their response to FCE 24517 within a species. Comparing the different progenitor cell response to FCE 24517, canine CFU-gm and CFU-e were 26- to 221-fold more sensitive to this drug's toxic effects than their human and murine counterparts. This was demonstrated by extremely low IC70 values for the canine CFU-gm (0.001 nM) and CFU-e (0.007 nM). Murine progenitors displayed 1.3- to 10.9-times higher IC70 values than human CFU-gm, BFU-e and CFU-e following 4 hr exposure to FCE 24517. The data demonstrated that a mouse model may better predict human in vitro myelotoxicity to FCE 24517 than beagle dogs.