Pharmacokinetics, tissue distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II) in dogs

The pharmacokinetics, tissue distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II) (SKI 2053R), a new potential anticancer agent, were investigated in dogs after a single intravenous administration of [14C]SKI 2053R (7 mg/kg, 100 microCi/kg). Total radioactivity in the plasma and ultrafiltrable plasma declined in a biexponential fashion with the initial half-lives of 0.63 +/- 0.05 hr (mean +/- SD) and 0.53 +/- 0.05 hr, and with the terminal half-lives of 51.08 +/- 3.26 hr and 15.19 +/- 3.75 hr, respectively. Radioactivity was well distributed into all tissues except the central nervous system. The majority of the radioactivity was found in the gastrointestinal contents, urine, and organs of elimination at all time points. The distribution pattern of [14C]SKI 2053R in the whole-body autoradiograms was consistent with that observed by the measurement of tissue concentrations. The 0-7 days cumulative urinary and fecal recoveries of total radioactivity were 87.30 +/- 2.93% and 8.68 +/- 1.30%, respectively, resulting in a total recovery of 95.98 +/- 1.61% of the administered dose. A large portion of [14C]SKI 2053R was distributed into the cellular fraction of mouse or rat blood, but was not into that of dog or human blood in vitro. The in vitro and in vivo binding of [14C]SKI 2053R to plasma protein was minimal to moderate.

Diagnostic value of 169Yb-cis-dichlorodimethionine platinum scintigraphy in patients with malignant lymphomas

Ytterbium-169 (169Yb) cis-dichlorodimethionine platinum (169Yb-PtCl2Meth2) is a new agent of low toxicity with an affinity for neoplastic tumours. The aim of this study was to assess the diagnostic value of 169Yb-PtCl2Meth2 scintigraphy in patients with malignant lymphomas. 169Yb-PtCl2Meth2 scintigraphy was performed in 67 patients with histologically proven malignant lymphoma. Liver, spleen, kidney and bone were among the normal tissues that showed uptake of the radiopharmaceutical. The compound is excreted in the main through the urinary tract. There was no significant activity in the bowels. For evaluation of the images, uptake of activity was scored according to a 5-point scale. In total, 888 sites were evaluated. The sensitivity, specificity and accuracy of lymphoma detection for the body as a whole was 80, 89 and 87%, respectively. The best results were obtained for the head (sensitivity 91%, specificity 89%), neck (sensitivity 84%, specificity 90%) and chest (sensitivity 82%, specificity 84%). In the sub-diaphragmatic region, sensitivity and specificity were 76 and 84%, respectively. Scintigraphy with 169Yb-PtCl2Meth2 appears to be a sensitive, non-invasive procedure for the staging of malignant lymphomas. The results suggest that it is possible to monitor the therapy of malignant lymphoma by means of 169Yb-PtCl2Meth2 scanning.

In vitro antitumor activity of a new platinum complex, cis-malonato [(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane] platinum (II) (SKI 2053R), against human lung and stomach cancer cell lines

The in vitro antitumor activity of a new platinum complex, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e] platinum(II) (SKI 2053R, NSC D644591), cisplatin (CDDP) and carboplatin (CBDCA) was determined against two human lung cancer (PC-9 and PC-14) and two human stomach cancer (MKN-45 and KATO III) cell lines by human tumor clonogenic assay. The activity of SKI 2053R was compared with those of CDDP and CBDCA in terms of relative antitumor activity (RAA, peak plasma concentration/IC50). Mean IC50 values (microgram/ml) of SKI 2053R, CDDP and CBDCA were 6.4 +/- 0.8, 1.8 +/- 0.7 and 20.6 +/- 12.2, respectively. The RAAs of SKI 2053R, CDDP and CBDCA were 1.6 +/- 0.4, 2.0 +/- 0.8 and 1.2 +/- 0.6, respectively. The differences in these values were not statistically significant. The results, demonstrating that antitumor activity of SKI 2053R is similar to those of CDDP and CBDCA, suggest that SKI 2053R is an interesting candidate for further development as a new anticancer drug.

Antitumor activity of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2- isopropyl-1,3-dioxolane]platinum(II), a new platinum analogue, as an anticancer agent

The in vitro and in vivo antitumor activity of a new antitumor platinum complex, cis-malonato[(4R, 5R)-4,5- bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) (SKI2053R, NSC D644591), were evaluated and compared with those of cisplatin (CDDP) and carboplatin (CBDCA) using murine tumors. SKI 2053R was highly active in vitro against both L1210 murine leukemia and its CDDP-resistant subline, L1210/DDP; the relative resistances were 20.0-, 14.5-, and 2.7-fold for CDDP, CBDCA, and SKI 2053R, respectively. SKI 2053R showed activity comparable with or superior to either CDDP or CBDCA in mice implanted with L1210. In mice implanted with L1210/DDP, as compared with CBDCA, SKI 2053R showed high values for the percentage of treated survivors relative to controls and for numbers of cured mice, whereas CDDP had virtually no activity. In mice implanted with P388, all three drugs were highly active, but the intensity of activity was shown to be ranked in the following order: SKI 2053R > CDDP > CBDCA. The antitumor activity of SKI 2053R against Lewis lung carcinoma was comparable with that of both CDDP and CBDCA. The antitumor activity of SKI 2053R was further investigated against two human tumor xenografts, KATO III (stomach adenocarcinoma) and WiDr (colon adenocarcinoma), implanted s.c. in nude mice and was compared with that of CDDP. In SKI 2053R-treated groups, the time required for a mean tumor weight of 1,000 mg was 33.1 days in KATO III xenografts and 35.0 days in WiDr xenografts as compared with 30.2 and 27.2 days in CDDP-treated groups, respectively. SKI 2053R achieved growth-inhibition rates comparable with those of CDDP against KATO III (65% versus 59%) and WiDr xenografts (64% versus 54%) on day 35. These results indicate that SKI 2053R is an attractive candidate for further development as a clinically useful anticancer drug.

General pharmacology of cis-malonato[4R,5R)-4,5-bis-(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II)

The general pharmacological properties of cis-malonato-[(4R,5R)-4,5- bis(aminomethyl)-2-isopropyl-1.3-dioxolane]platinum(II) (SKI 2053R, CAS 146665-77-2), a new potential anticancer agent, were investigated in mice, rats, guinea pigs, rabbits, cats and dogs. Intravenous administration of SKI 2053R had no effect on the central nervous system. SKI 2053R had no effect on the autonomic nervous system and smooth muscles except that it slightly inhibited the spontaneous motility of isolated rabbit ileum at a concentration of 5 x 10(-5) g/ml. SKI 2053R did not adversely affect the respiratory-cardiovascular system, gastrointestinal system, neuromuscular junction, or renal function. SKI 2053R did not significantly alter the levels of serum glucose, serum free fatty acid and plasma lactate, and did not induce hemolysis. SKI 2053R did not affect blood coagulation mechanism and liver function. SKI 2053R did not exhibit anti-inflammatory activity. It was observed that SKI 2053R increased the formation of hemolytic plaque by spleen cells of sensitized mice at high doses (10 mg/kg and 35 mg/kg). Therefore, it is concluded from these general pharmacological studies that SKI 2053R at the doses showing antitumor activity does not induce severe adverse effects on the central nervous, autonomic nervous, respiratory-cardiovascular, gastrointestinal, peripheral nervous, and other systems in experimental animals.

Homodinuclear (Pt,Pt) and heterodinuclear (Ru,Pt) metal compounds as DNA-protein cross-linking agents: potential suicide DNA lesions

Homodinuclear (Pt,Pt) and heterodinuclear (Ru,Pt) metal compounds having the generalized formula M(a)NH2(CH)4NH2M(b) are shown to form specific DNA lesions which can efficiently cross-link proteins to DNA. In this study, the homodinuclear case is represented by M(a) = M(b) = [cis-Pt(Cl2)-(NH3)] and the heterodinuclear case is represented by M(a) = [cis-RuCl2(DMSO)3] and M(b) = [cis-PtCl2(NH3)]. Native and denaturing polyacrylamide gel electrophoresis was used to show the formation of ternary coordination complexes between the metal-treated 49-bp DNA fragment and the Escherichia coli UvrA and UvrB DNA repair proteins. Treatment with proteinase K results in loss of the DNA-protein cross-links. DNA-protein cross-links formed between UvrA and DNA previously modified with the dinuclear metal compounds are reversible with the reducing agent beta-mercaptoethanol. The DNA lesion responsible for efficient DNA-protein cross-linking is most probably a DNA-DNA interstrand cross-link in which each metal atom is coordinated with one strand of the DNA helix. The formation of DNA repair protein associated DNA cross-links, potential "suicide adducts", suggests a novel action mechanism for these anticancer compounds. In addition, these dinuclear metal compounds should be very useful agents for the investigation of a wide range of protein-DNA interactions.

Synthesis and antitumor activity of a new cis-diammineplatinum (II) complex containing procaine hydrochloride

This paper refers to some of the chemical and biological properties of a new platinum (II) complex where the aromatic amino group of procaine is involved in the coordination with platinum and whose structure was defined by UV, IR, 1H-NMR, and elemental analysis. This new cationic platinum-triamine complex (DPR) displays excellent solubility (> 50 mg/ml) and stability in water. DPR has significant in vitro cytotoxicity against murine P388 leukemic cell line, human K562 erythroleukemic cell line and human Jurkat T cell line. The in vitro cytotoxic effects of DPR on P388 and Jurkat leukemic cells were comparable to those of cis-diamminedichloroplatinum (II) (DDP), while its activity on K562 cells was significantly better than that of DDP [IC50 = 1.07 +/- 0.36 (SD) microM vs 2.62 +/- 0.23 (SD) microM, P < 0.01]. The in vitro Pt accumulation rate for P388 cells was twice as rapid after DPR than after DDP exposure, while no difference in cellular platinum efflux was observed. The antitumor activity of DPR was tested in vivo against P388 leukemic cells in BDF1 mice and gave a % ILS value (75%) similar to that of the maximum tolerated dose (MTD) of DDP (8 mg/Kg). A comparative study of plasma urea nitrogen (PUN) levels and kidney morphological analysis in tumor-bearing mice receiving the LD50 dose of both drugs (39.3 mg/Kg and 16.5 mg/Kg for DPR and DDP, respectively), showed DPR to be less nephrotoxic than DDP. These results indicate that this new cationic platinum-triamine complex containing primary amine ligand is surprisingly active both in vitro and in vivo. In summary, the good characteristics of DPR in terms of high solubility, encouraging anticancer activity and absence of nephrotoxic effects make DPR a promising new platinum anticancer agent for preclinical development.

Light-microscopic detection of acidic glycoconjugates with sensitized diamine procedures

To enhance the efficiency and specificity of diamine methods in light microscopy, these methods were sensitized by silver enhancement in combination with trichloro(ethylene) platinate (KTP). The sensitized diamine methods consisted of a diamine (high or low iron diamine: HID or LID), KTP, borohydride reduction (BH) and a physical development (PD) sequence. The new methods have been successfully applied to routinely prepared tissue sections obtained from rat organs, such as salivary glands, stomach, colon, kidney, lung and trachea. In the tissues subjected to the sensitized diamine methods, weakly diamine-stained histological structures exhibited vivid positive reactions. The combined sensitized diamine methods and selective procedures, such as enzyme digestion and chemical modification, have substantiated that these methods were of sufficient efficiency and specificity.

Pyruvate uptake induced by a pH jump in mesophyll chloroplasts of maize and sorghum, NADP-malic enzyme type C4 species

A sudden pH decrease (pH jump) of the medium enhanced pyruvate uptake in the dark in mesophyll chloroplasts (MCp) of Zea mays and Sorghum bicolor, NADP-malic enzyme type C4 plants, while it was reported that a Na+ jump enhanced pyruvate uptake in MCp of P. miliaceum, a NAD-malic enzyme type [(1987) FEBS Lett. 219, 347]. The enhancement effect of the pH jump decayed completely in 5 min and the decay was accelerated by proton gradient-collapsing reagents. The results suggest that active pyruvate uptake into MCp of NADP-malic enzyme type C4 species is primarily driven by the proton gradient across the envelope.

Catalytic activity of the serine proteases alpha-chymotrypsin and alpha-lytic protease tagged at the active site with a (terpyridine)platinum(II) chromophore

Incubation of alpha-chymotrypsin and alpha-lytic protease with chloro(2,2':6',2''-terpyridine)platinum(II), [Pt(trpy)Cl]+, results in attachment of Pt(trpy)2+ tags at both His 57 and His 40 in the former and His 57 in the latter. The [Pt(trpy)His]2+ chromophores are readily detected and quantitated owing to their characteristic, strong UV absorption. Although the tagging of His 57 modifies the catalytic triad (Ser 195, His 57, and Asp 102) and disrupts the charge relay, the platinated enzymes retain significant esterase and amidase activity for both specific and nonspecific substrates. Unlike suicide inhibitors, which inactivate the enzymes by filling the active site and imitating the tetrahedral intermediate, [Pt(trpy)Cl]+ reacts with a particular amino acid and permits binding of substrates. The kinetic constants for the following are reported: two esters and two amides with alpha-chymotrypsin and an amide with alpha-lytic protease. The kcat values are between 1 and 25% of, and the Km values are a little higher than, the corresponding values for the native enzymes. The catalytic activity is not due to the native enzymes, trypsin, or some zinc-containing protease. Activities of the native and of the platinated alpha-chymotrypsin depend similarly on pH although the pKa of His 57 is raised to 9.7 upon platination. The platinated enzymes undergo autodigestion slower than do the native enzymes. Because the Pt(trpy)2+ tags are noninvasive, stable, and yet easily removable by thiourea, [Pt(trpy)Cl]+ may be used to retard autodigestion of stored proteolytic enzymes.

Antibodies against (1R,2R)-cyclohexanediamineplatinum(II)-DNA adduct recognize the conformational differences of isomeric analogues of cyclohexanediamine

Antibodies reactive to (1R,2R)-cyclohexanediamineplatinum(II)-DNA ((1R,2R)-cyclohexanediamine: 1R,2R-dach) adducts were elicited by immunization of rabbit with calf thymus DNA modified by Pt(1R,2R-dach)Cl2 at a ratio of bound platinum per nucleotide ((D/N)b) of 0.0335. In an enzyme-linked immunosorbent assay (ELISA), the binding of specific antibodies to Pt(1R,2R-dach)-DNA adduct (60 microliters of 1.235 x 10(-7) M Pt in each wells) on the assay plate was competitively inhibited by Pt(1R,2R-dach)-DNA adduct ((D/N)b = 0.0653) in the solution. Almost equal inhibition was observed with Pt(1S,2S-dach)-DNA ((D/N)b = 0.0412), an optical isomer of 1R,2R-dach. Pt(1R,2S-dach)-DNA ((D/N)b = 0.0371) and Pt(1R,3S-dach)-DNA ((D/N)b = 0.0281) in which the cyclohexane ring is stereochemically perpendicular to the platinum chelate plane, also inhibited antibody binding, but these adducts gave only incomplete inhibition at higher Pt-DNA adduct concentrations. Although Pt(1R,2R-dach)-d(GpG) and Pt(1R,2R-dach)(NH3)2 inhibited antibody binding, the affinity of the antibody for Pt(1R,2R-dach)(NH3)2 was lower than with Pt(1R,2R-dach)-DNA, and the inhibition behavior of Pt(1R,2R-dach)-d(GpG) was biphasic, i.e., at the lower concentration the inhibition curve was consistent with that of Pt(1R,2R-dach)-DNA, but at the higher concentration it shifted to that of Pt(1R,2R-dach)(NH3)2. The affinity of the antibody for cis-DDP was markedly lower than with Pt(1R,2R-dach)(NH3)2. These facts suggest that the antibodies may bind to the substituents (the platinum and its surroundings) of the various Pt complexes rather than the DNA structure altered by platinum binding.

Use of a surface-acoustic-wave sensor to characterize the reaction of styrene vapor with a square-planar organoplatinum complex

A coated surface-acoustic-wave (SAW) sensor is used to probe the reaction of styrene vapor with the square-planar platinum-ethylene pi-complex, trans-PtCl2(ethylene)(pyridine). A dual-SAW delay-line oscillator configuration is employed: one oscillator is coated with a solvent-cast film of the solid platinum-ethylene complex dispersed in a poly(isobutylene) matrix, and the second oscillator is coated only with polymer. Absorbed styrene vapor displaces ethylene to form the stable styrene-substituted complex, trans-PtCl2(styrene)(pyridine), causing a decrease in the oscillator frequency from the increase of mass on the surface of the sensor. For short-term exposures, there is a linear relationship between the logarithm of the rate of frequency change and the logarithm of the styrene vapor concentration, consistent with a power-law kinetic model for the heterogeneous trapping reaction. Deviation from this relationship above 300 ppm at 25 degrees C is attributed to the onset of multilayer adsorption of styrene at the surface of the trapping reagent. The sensor response exhibits an Arrhenius temperature dependence permitting estimation of the thermal activation energy for the olefin-substitution reaction. Calculated detection limits of 3 and 0.6 ppm of styrene vapor are achieved for operation at 25 and 40 degrees C, respectively.

NMR studies of an oligonucleotide with an unusual structure induced by platinum anti-cancer drugs

The 31P NMR spectra of Pt(en)[d(T1A2T3G4G5G6T7A8C9C10C11A12T13A14)] (14-mer) and Pt(en)[d(A2T3G4G5G6T7A8C9C10C11A12T13)] (12-mer) (en = ethylenediamine) each contain two signals far downfield (ca. -2.9 and -2.6 ppm from trimethylphosphate standard), two signals slightly downfield, and at least one signal slightly upfield of the normal range (ca -4.0 to -4.4 ppm). This pattern suggested a distorted structure. The unusual 31P signals of the 12-mer were assigned by analogy to signals of the 14-mer previously assigned by 17O-labeling methods. A combination of heteronuclear multiple-quantum coherence, one-dimensional and two-dimensional nuclear Overhauser effect (1D and 2D-NOE) and homonuclear shift correlation spectroscopy (COSY) experiments assigned all aromatic 1H signals of the 12-mer except H8 of G5 or G6. One of these H8 signals is missing from the spectrum and the nucleotide is labeled Gm. The other H8 is the most downfield signal and has a strong NOE to its H1'. Since this strong NOE indicates that this nucleoside exists in a syn conformation, it is labeled Gs. A strong NOE was observed between the Gs and A8 H8 signals. Several lines of evidence suggested a hairpin-like structure with a loop region (G6T7A8C9) and a stem region involving A2T3G4G5 and C10C11A12T13. The 31P signals for the stem region are within or slightly outside the normal range. 3JH3'-P values (3-6 Hz), measured by a 2D-J experiment, of stem nucleotides were characteristic for a DNA duplex. Imino signals for base pairs A2T13, T3A12, G4C11, and probably G5C10, and the observation of internucleotide NOE connectivities for these nucleotides (e.g. between an H8 signal and the H1' signal of the 5' nucleotide) suggested a right-handed helical structure. For the loop region, a distorted sugar-phosphate backbone is indicated by far downfield positions of the G5pG6 and A8pC9 31P signals, the 3JH3'-P values for C9p (8.0 Hz) and A8p (6.8 Hz), and the absence of H3'-P coupling for G5p. In the loop region, no imino signals or internucleotide NOEs characteristic of a right-handed duplex were observed. However, A8H8, C9H6, and C10H6 each exhibited unusual internucleotide NOEs to the H4' signal of the 5' residue. NOE crosspeaks between T7 1H signals and signals attributed to sugars of the Gs and Gm suggested that the T7 moiety is located within the space encircled by the loop. The few NOE crosspeaks, pH dependence, and Cu2+ broadening of C9 1H signals indicate an isolated location accessible to solvent.(ABSTRACT TRUNCATED AT 400 WORDS)

Selective real-time measurement of styrene vapor using a surface-acoustic-wave sensor with a regenerable organoplatinum coating

The performance of a coated surface-acoustic-wave (SAW) sensor for monitoring styrene vapor is investigated. The effects of several organic co-contaminants and atmospheric humidity are described, and regeneration of the sensor coating is demonstrated. The dual-SAW delay-line oscillator employs a reagent coating of trans-PtCl2(ethylene)(pyridine) to trap styrene via ethylene substitution. The rate of change of the sensor frequency is used to provide real-time measurement of styrene vapor concentrations. No effect on the response to styrene is observed upon simultaneous exposure to each of several olefin and non-olefin solvent vapors used with styrene in industrial processes. Butadiene, however, presents a reversible negative interference by successfully competing with styrene for reaction with the trapping agent. The response to styrene exhibits a moderate positive humidity dependence. Following prolonged exposure, the original complex can be regenerated in situ by exposure to ethylene gas, permitting repeated use of the sensor. An emphasis is placed on the application of the sensor to workplace air monitoring.

Synthesis and characterization of novel biologically active platinum(II) and palladium(II) complexes of some beta-carboline alkaloids

The preparation of novel biologically active platinum(II) and palladium(II) complexes of some beta-carboline alkaloids (harmaline, harmalol, harmine, and harmane) is described. These complexes, characterized on the basis of their CHN elemental analysis, infrared, Raman and 1H and 13C nuclear resonance spectral data, were shown to have the empirical formula [M(alkaloid)Cl2], M = Pt, Pd. The antitumor and antiviral activities of some of these complexes have been demonstrated.

32P-postlabelling of 7-methyl-dGMP ring-opened 7-methyl-dGMP and platinated dGpdG

The 32P-postlabelling technique introduced by Randerath and coworkers was used to investigate the efficiency of the phosphorylation reaction by T4 polynucleotide kinase using three synthesized adducts: 7-methyl-dGMP, ring-opened 7-methyl-dGMP and platinated dGpdG. The methylated substrates were detected at sub-fmol sensitivities. 7-Methyl-dGMP was quantitatively phosphorylated at these low concentrations. The efficiency of phosphorylation of the ring-opened product was less (about one order of magnitude) and that of Pt(dGpdG) about three orders of magnitude less. These results show that T4 polynucleotide kinase phosphorylation is an efficient reaction with 7-methyl-dGMP and with ring-opened 7-methyl-dGMP, even though in the latter case longer incubation times may have to be used to boost the reaction towards completion. By contrast, the low level of phosphorylation with Pt(dGpdG) does not appear encouraging for quantitative determination requiring a high sensitivity.

Tissue injury and repair in the rat kidney after exposure to cisplatin or carboplatin

Cisplatin (cis-diamminedichloroplatinum II) has emerged as an anticancer drug of considerable value for the chemotherapy of several human neoplasms. However, this agent often causes renal toxicity, which appears to be the dose-limiting untoward effect. The present animal study was undertaken to compare, with regard to kidney injury and renal tissue repair, cisplatin and carboplatin (cis-diammine-1,1-cyclobutane dicarboxylate platinum II), a platinum derivative more recently introduced in clinics. Female Sprague-Dawley rats (four animals per group) were treated ip with cisplatin (4 or 8 mg/kg, delivered in four consecutive daily injections) or carboplatin (40 mg/kg given in one injection) and terminated 4, 7, and 21 days after drug administration. One hour prior to sacrifice, each animal received ip 200 microCi of [3H]thymidine for the measurement of DNA synthesis and cell proliferation (frequency of S-phase cells in renal tissue, determined by histoautoradiography). Cisplatin, particularly at 8 mg/kg, caused severe tubular injury (acute tubular necrosis) culminating in a long-lasting cystic tubular dilatation in the outer stripe of outer medulla. Tubular damage was followed by a sharp proliferative response, indicative of tubular regeneration. However, the proliferative activity was still above basal level at the end of the observation period, suggesting that the tissue repair process had not reached completeness 3 weeks after cisplatin administration. In contrast, carboplatin only induced focal tubular necrosis in proximal tubules. Distal and collecting tubules also showed ultrastructural evidence of hydropic degeneration after exposure to the latter drug. Renal tubular injury associated with carboplatin was followed by a mild proliferative response. From this study, we can infer that carboplatin is less nephrotoxic than cisplatin, but still causes histopathological alterations in renal tissue. Furthermore, the lesser nephrotoxicity of carboplatin has a primary origin and is not due to a more efficient tissue repair reaction.

Reaction of (R)-(-)-2-aminomethylpyrrolidine(1,1-cyclobutanedicarboxylato)platinum( II) with guanosine

The reaction of a new antitumor platinum complex, (R)-(-)-2-aminomethylpyrrolidine(1,1-cyclobutanedicarboxylato++ +)platinum(II) (1) with guanosine at room temperature in an aqueous solution was followed by proton nuclear magnetic resonance (1H-NMR) spectroscopy and high performance liquid chromatography (HPLC) at intervals. Both techniques showed that a new compound was formed by displacement of the 1,1-cyclobutanedicarboxylate moiety of 1 with two guanosines, and its 1H-NMR spectrum and HPLC chromatogram were proved to be identical with those of [(R)-(-)-2-aminomethylpyrrolidine]bis(N7-guanosine)platinum(II) (2), which was obtained upon successive treatment of (R)-(-)-2-aminomethylpyrrolidinedichloroplatinum(II) (3) with AgNO3 and 2 mol eq of guanosine in water. The binding sites of the platinum to the two guanosine moieties in 2 were confirmed by the pH dependence of the two G-H8 signals.

Improved medium for recovery and enumeration of the farmer's lung organism, Saccharomonospora viridis

A new medium, which we propose to call R8, was developed for the isolation and enumeration of the thermophilic actinomycete, Saccharomonospora viridis. This organism has been implicated in a range of hypersensitivity pneumonitides, including farmer's lung, but is generally isolated in small numbers from contaminated environments. Recovery of S. viridis from moldy hay and mushroom compost on R8 medium was compared with recovery on conventional media. S. viridis was isolated from both substrates but in highest numbers and most consistently on the R8 medium. The selectivity of this medium was best observed when the sedimentation chamber method was used for hay samples. Here S. viridis accounted for up to 80% of the total number of actinomycetes recovered on R8 and could not be recovered on rifampin selective medium under the same conditions. R8 was also found to be an efficient recovery medium for a range of thermophilic actinomycetes from mushroom compost and for another allergenic species, Faenia rectivirgula, from moldy hay. Contamination of isolation plates by thermophilic bacilli was reduced on R8 compared with the activity on half-strength tryptone soy agar, supplemented with 0.2% casein hydrolysate, and this, together with specific improvements in S. viridis growth, accounts for the selective effect. It is possible that the occurrence of S. viridis and its role as a causative agent of hypersensitivity pnuemonitis have been underestimated by the use of suboptimal recovery protocols. It is hoped that use of R8 in conjunction with dilution plate techniques will generate information on the ecology of S. viridis and contribute to health risk assessment studies.

trans-dichlorobis(di-n-propyl sulfoxide)platinum(II)

[PtCl2(C6H14OS)2], Mr = 534.48, monoclinic, P2(1)/c, a = 9.092 (2), b = 5.696 (2), c = 19.749 (7) A, beta = 110.63 (3) degrees, V = 957.2 (6) A3, Z = 2, D chi = 1.854 Mg m-3, lambda(Mo K alpha) = 0.71069 A, mu(Mo K alpha) = 7.894 mm-1, F(000) = 520, room temperature, R = 0.047 for 1842 unique observed reflections. The Pt atom is located on a center of symmetry. Pt has trans square-planar coordination and the sulfoxide ligands are bonded through their S atoms. The Pt-Cl bond distances are 2.292 (3) A. The Pt-S bond lengths [2.292 (2) A] are significantly longer than the corresponding distances in the cis isomer. The packing consists of layers of molecules parallel to the ab plane.

Structure of a styrylbenzothiazole platinum(II) complex: [NEt4][PtBr3(asb)]

Tetraethylammonium tribromo[2-(2- acetoxystyryl)benzothiazole]platinate(II), [(C2H5)4N]-[PtBr3(C17H13NO2S)], Mr = 860.4 monoclinic, P21/c, a = 11.230 (9), b = 19.333 (4), c = 13.685 (6) A, beta = 101.06 (4) degrees, V = 2916 (4) A3, Z = 4, D chi = 1.96 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 90.3 cm-1, F(000) = 1648, T = 296 K, final R = 0.047 for 3384 unique observed reflections. The [PtBr3(asb)]- unit has square-planar geometry about the Pt, with the asb coordinated to the Pt through the N of the thiazole ring and a Pt-N bond distance of 2.010 (8) A. The average Pt-Br distance is 2.426 (7) A. The ligand is non-planar with a dihedral angle of 22.4 (7) degrees between the benzothiazole and the acetoxybenzene rings. The dihedral angles between the platinum coordination plane and the benzothiazole and benzene rings are 85.7 (1) and 71.3 (3) degrees respectively.

Effect of hyperthermia on cis-diamminedichloroplatinum(II) (rhodamine 123)2[tetrachloroplatinum(II)] in a human squamous cell carcinoma line and a cis-diamminedichloroplatinum(II)-resistant subline

The effect of concomitant hyperthermia on the cytotoxicities of cis-diamminedichloroplatinum(II) (CDDP), a newly synthesized drug, Pt(Rh-123)2, and its chemical components, K2PtCl4 and rhodamine 123, was examined in vitro in a squamous cell tumor line of human origin (SCC-25) and in a CDDP-resistant subline (SCC-25/CP). No difference in the cytotoxicity of hyperthermia alone was observed between these cell lines. The dose-dependent cytotoxicities of 1-h exposures to CDDP and Pt(Rh-123)2 were markedly increased at 42 degrees C and 43 degrees C in comparison to 37 degrees C, and this effect was of the same magnitude in both cell lines (enhancements of approximately 1.5 logs at 42 degrees C and 2.5 logs at 43 degrees C for CDDP and 1.5 logs at 42 degrees C and greater than 3 logs at 43 degrees C for Pt(Rh-123)2). The use of hyperthermia with CDDP, however, did not lower survivals in the SCC-25/CP cells even to the levels seen in the parent line at 37 degrees C. The cytotoxicities of K2PtCl4 and rhodamine 123 were essentially the same in the CDDP-sensitive and -resistant cells at all temperatures tested. The magnitude of the temperature effect was significantly greater for Pt(Rh-123)2 than for its chemical components. No significant effect on CDDP or Pt(Rh-123)2 accumulation was observed at 42, 43, 44 or 45 degrees C in either cell line. DNA lesions, measured by alkaline elution, were significantly enhanced for CDDP in the SCC-25 cells at 42 degrees C. These results suggest that treatment with hyperthermia and either CDDP or Pt(Rh-123)2 should result in supraadditive anti-tumor effects, although the efficacy of CDDP plus hyperthermia will be significantly less once resistance to CDDP has developed. Since resistance to CDDP does not imply cross-resistance to Pt(Rh-123)2, and since the effect of hyperthermia is somewhat greater for Pt(Rh-123)2 than for CDDP at 43 degrees C, Pt(Rh-123)2 may be more selectively toxic to tumor cells when used with local hyperthermia versus normal cells outside the treated area, especially if resistance to CDDP has already developed.

Displacement of the bidentate malonate ligand from (d,l-trans-1,2-diaminocyclohexane)malonatoplatinum(II) by physiologically important compounds in vitro

Previous studies of platinum(II) compounds with bidentate leaving ligands have emphasized the contrast between the stability of the bidentate leaving ligand in vitro (T1/2 greater than 11 days in water) and the apparent reactivity of these bidentate platinum compounds in vivo. However, none of these studies actually measured the stability of these compounds in tissue culture medium (or in any other reaction mixture resembling in vivo conditions). The experiments described in this paper were designed to measure the stability and fate of (d,l-trans-1,2-diaminocyclohexane)malonatoplatinum(II) [Pt(mal)(trans-dach)] in RPMI-1640 tissue culture medium. The T1/2 for displacement of the malonate ligand in this medium was 9.5 hr at 37 degrees. Of the inorganic anions present in the medium, chloride accounted for the greatest displacement of the malonate ligand. However, at the concentrations with which it is found in tissue culture medium and in blood, bicarbonate was nearly as effective as chloride at displacing the malonate ligand. This observation is of particular significance because the bicarbonatoplatinum complex is unstable and the bicarbonate displacement reaction appears to represent a major non-enzymatic pathway for the formation of the biologically active aquated platinum complexes. At the concentrations with which they occur inside the cell, phosphates may play a similar role. Of the amino acids present in the medium, glutathione and the sulfur-containing amino acids were 50- to 400-fold more effective at displacing the malonate ligand than the other amino acids in RPMI-1640 medium. In the case of methionine, the reaction with Pt(mal)(trans-dach) was shown to be a direct displacement (SN2) reaction at physiological methionine concentrations. When Pt(mal)(trans-dach) was incubated at 37 degrees for 24 hr in RPMI-1640 medium, the major transformation products formed were (d,l-trans-1,2-diaminocyclohexane)methionineplatinum(II) (38%), other amino acid-platinum complexes (19%), and (d,l,-trans-1,2-diaminocyclohexane)dichloroplatinum(II) (14%). Eleven percent of the Pt(mal)(trans-dach) remained intact. Mass spectrometry and 1H-NMR indicated that the (d,l-trans-1,2-diaminocyclohexane)methionineplatinum(II) complexes that formed in RPMI-1640 medium consisted of approximately 60% of the bidentate mono-methionine complex coordinated to platinum at the sulfur and alpha-amino positions and 40% of the bis-methionine complex, presumably coordinated at the sulfurs.(ABSTRACT TRUNCATED AT 400 WORDS)

rRNA-protein neighbourhood in Escherichia coli 70 S ribosomes and 70 S initiation complex. Probing by bifunctional Pt(II)-containing reagent

The cleavable homobifunctional reagent dichloro[N,N,N',N'-tetrakis(2-aminoethyl)-1,6-hexamethylenediamminedi platinum (II)] dichloride was used for studying rRNA-protein cross-links in free 35S-labelled 70 S ribosomes and within initiation complex ribosome.AUGU6.fMet-tRNA(fMet). It was shown that the sets of proteins cross-linked to 16 S and 23 S rRNA in free 70 S ribosomes and in 70 S initiation complex do not differ significantly. The authors are the first to demonstrate most of the 23 S rRNA-protein cross-links and some 16 S rRNA-protein cross-links, in particular those with L7/L12 protein.