Cariprazine, A Dopamine D₂/D₃ Receptor Partial Agonist, Modulates ABCG2-Mediated Multidrug Resistance in Cancer

Multidrug resistance (MDR) is a continuing clinical problem that limits the efficacy of chemotherapy in cancer. The over expression of the ATP-binding cassette (ABC) family G2 (ABCG2) transporter is one of the main mechanisms that mediates MDR in cancer. Molecular modeling data indicated that cariprazine, a dopamine D₂/D₃ receptor partial agonist, had a significant binding affinity for ABCG2 transporter with a Glide XP score of -6.515. Therefore, in this in vitro study, we determined the effect of cariprazine on MDR resulting from the overexpression of ABCG2 transporters. Alone, cariprazine, at concentrations up to 20 μM, did not significantly decrease cell viability. Cariprazine, at concentrations ranging from 1 to 10 μM, did not significantly alter the cytotoxicity of mitoxantrone (MX) in the parental non-small cell cancer cell line, H460 and colon cancer cell S1. However, cariprazine (1⁻20 μM) significantly enhanced the efficacy of ABCG2 substrate antineoplastic drug MX in the ABCG2-overexpressing MDR cell line, H460-MX20 and S1M1-80, by reducing the resistance fold from 28 to 1 and from 93 to 1.33, respectively. Cariprazine, in a concentration-dependent (1⁻20 μM), significantly increased the intracellular accumulation of Rhodamine 123 in S1M1-80. Interestingly, 10 or 20 μM of cariprazine significantly decreased the expression levels of the ABCG2 protein in the colon and lung cancer cell lines, suggesting that cariprazine inhibits both the function and expression of ABCG2 transporters at nontoxic concentrations. Overall, our results suggest that cariprazine, via several distinct mechanisms, can resensitize resistant cancer cells to mitoxantrone.

Impact of a comprehensive telephone-based disease management programme on quality-of-life in patients with heart failure

BACKGROUND

Disease management programmes for patients with heart failure have improving the quality-of-life (QOL) of patients with heart failure.

METHODS

Patients attending the heart failure clinic were randomized into 2 groups of 25 patients each. The control group was managed in the heart failure clinic and the intervention group underwent the following additional interventions: (i) interactive sessions with the patient and spouse informing them about the disease, drugs, and self-management of fluid intake and diuretic dose; (ii) a telephonic helpline was established and regular telephone calls made to reinforce the information and modify drug dosages. The QOL was assessed using the Kansas City Cardiomyopathy questionnaire. Functional capacity was assessed by the 6-minute walk test. Continuous variables were compared with the Student t-test (paired or unpaired).

RESULTS

There was significant improvement in the QOL and functional capacity of patients in the intervention group compared with controls over a 6-month period. The mean (SD) QOL scores in the intervention group improved from 60.0 (23.6) to 76.3 (17.3) but did not change significantly in the control group (62.2 [22.6] to 63.4 [21.9]). There was a similar improvement in the functional capacity measured by the 6-minute walk test in the intervention group (from 202.2 [81.5] to 238.1 [100.9] metres, p < 0.05) but not in the control group (193.8 [81.5] to 179.7 [112.0] metres). In the intervention group, the use of beta-blockers and angiotensin-converting enzyme inhibitors was similar but in the intervention group patients were placed on higher doses. There was no significant difference in the number of emergency room visits or admissions in either group. For every 20 patients in the intervention group, 14 patients improved by 1 functional class while in the control group this was observed in only 3 patients for every 20 treated.

CONCLUSION

This study demonstrates that in the setting of a developing country, improvement in QOL by intensive management of heart failure patients through a heart failure programme with telephonic reinforcement and a helpline is greater than that usually achieved with drug therapy in a routine heart failure clinic.

Lepromatous leprosy with bilateral facial nerve palsy and hyperthyroidism

Bilateral lagophthalmos secondary to facial nerve is extremely uncommon. Further, the aetiology in most of these cases is of central origin unlike the peripheral involvement in leprosy. A patient of lepromatous leprosy (LL) may be euthyroid or hypothyroid on account of leprous involvement of the thyroid gland. A case of LL with bilateral lagophthalmos and hyperthyroidism is reported.

Polynitrogen chemistry. Synthesis, characterization, and crystal structure of surprisingly stable fluoroantimonate salts of N5+

The new N5+ salt, N5+ SbF(6)(-), was prepared from N(2)F(+)SbF(6)(-) and HN(3) in anhydrous HF solution. The white solid is surprisingly stable, decomposing only at 70 degrees C, and is relatively insensitive to impact. Its vibrational spectrum exhibits all nine fundamentals with frequencies that are in excellent agreement with the theoretical calculations for a five-atomic V-shaped ion of C(2)(v)symmetry. The N5+ Sb(2)F(11)(-) salt was also prepared, and its crystal structure was determined. The geometry previously predicted for free gaseous N5+ from theoretical calculations was confirmed within experimental error. The Sb(2)F(11)(-) anions exhibit an unusual geometry with eclipsed SbF(4) groups due to interionic bridging with the N5+ cations. The N5+ cation is a powerful one-electron oxidizer. It readily oxidizes NO, NO(2), and Br(2) but fails to oxidize Cl(2), Xe, or O(2).

Structure of the SO(2)F(-) anion, a problem case

Recently, room-temperature crystal structures of SO(2)F(-) in its K(+) and Rb(+) salts were published in Z. Anorg. Allg. Chem. 1999, 625, 385 and claimed to represent the first reliable geometries for SO(2)F(-). However, their almost identical S-O and S-F bond lengths and O-S-O and O-S-F bond angles are in sharp contrast to the results from theoretical calculations. To clarify this discrepancy, the new [(CH(3))(2)N](3)SO(+) and the known [N(CH(3))(4)(+)], [(CH(3))(2)N](3)S(+), and K(+) salts of SO(2)F(-) were prepared and their crystal structures studied at low temperatures. Furthermore, the results from previous RHF and MP2 calculations were confirmed at the RHF, B3LYP, and CCSD(T) levels of theory using different basis sets. It is shown that all the SO(2)F(-) salts studied so far exhibit varying degrees of oxygen/fluorine and, in some cases, oxygen-site disorders, with [(CH(3))(2)N](3)SO(+)SO(2)F(-) at 113 K showing the least disorder with r(S-F) - r(S-O) = 17 pm and angle(O-S-O) - angle(F-S-O) = 6 degrees. Refinement of the disorder occupancy factors and extrapolation of the observed bond distances for zero disorder resulted in a geometry very close to that predicted by theory. The correctness of the theoretical predictions for SO(2)F(-) is further supported by the good agreement between the calculated and the experimentally observed vibrational frequencies and their comparison with those of isoelectronic ClO(2)F. A normal coordinate analysis of SO(2)F(-) confirms the weakness of the S-F bond with a stretching force constant of only 1.63 mdyn/A and shows that there is no highly characteristic S-F stretching mode. The S-F stretch strongly couples with the SO(2) deformation modes and is concentrated in the two lowest a' frequencies.

Ethyl 5-methyl-4-(2,5,5-trimethyl-1, 3-dioxan-2-yl)isoxazole-3-carboxylate

The title compound, C(14)H(21)NO(5), possesses an isoxazolyl group in the axial position of the 1,3-dioxanyl ring. The two rings are rotated about the bond joining them such that the two C(methyl)-C(dioxanyl)-C-C torsion angles are 92.1 (2) and -84.1 (2) degrees. In this conformation, neither the methyl nor ethoxycarbonyl substituents on the isoxazole are presented towards the dioxanyl chair.

Formation of a tetranuclear copper (II) cluster assembled by metal-assisted hydrolysis and desulfurization of bis(3,5-dimethylpyrazolyl)methylphosphine sulfide, MeP(S)(3,5-Me2Pz)2

The reaction of methylphosphine sulfide, MeP(S)(3,5-Me2Pz)2, 1, with anhydrous CuCl2 affords a tetranuclear copper cluster[Cu2Cl2(3,5-Me2Pz)3(MePO3)]2, 2, and a dinuclear compound Cu2Cl4(3,5-Me2Pz)4, 3. This reaction involves a metal-assisted desulfurization along with concomitant hydrolysis of P-N bonds. The X-ray structures of 1-3 have been determined, and the crystal parameters for these are the following. 1: space group = C2/c, a = 15.2552(1) A, b = 8.7364(2) A, c = 21.4490(3) A, beta = 93.349(1) degrees, V = 2853.74(8) A3, and Z = 8. 2: space group = P2(1)/n, a = 12.5964(4) A, b = 15.7773(4) A, c = 13.9781(4) A, beta = 116.6280(10) degrees, V = 2483.32(12) A3, and Z = 2. 3: space group = P2(1)/c, a = 8.7137(8) A, b = 13.5493(14) A, c = 11.8847(12) A, beta = 106.179(2) degrees, V = 1347.6(2) A3, and Z = 2. The structure of 2 shows that it comprises two dinuclear copper cores bridged together by two tripodal methylphosphinate, MePO3, ligands. 2 is weakly antiferromagnetically coupled, as revealed by variable temperature magnetic susceptibility measurements.

A novel synthesis of hexakis(trifluoromethyl)cyclotriphosphazene. Single-crystal X-ray structures of N3P3(CF3)6 and N3P3F6

Reaction of hexafluorocyclotriphosphazene (N3P3F6) with trimethyl(trifluoromethyl)silane in the presence of a catalytic amount of cesium fluoride in THF produced hexakis(trifluoromethyl)cyclotriphosphazene [N3P3(CF3)6] in 90% isolated yield. N3P3(CF3)6 is fully characterized by melting point, IR, NMR (19F, 13C, 31p), MS, and elemental analysis data. Single-crystal X-ray structures of N3P3(CF3)6 and N3P3F6 are reported.

Lack of maternal antibodies to P serotypes may predispose neonates to infections with unusual rotavirus strains

Rotavirus (RV) strains infecting newborns often have unique neutralization antigens (P serotypes) on their outer capsids that are distinct from those found on RV strains that cause diarrhea in older children. We examined the hypothesis that unusual RV strains preferentially infect newborns because the newborns lack maternal neutralizing antibodies to these strains. To test this hypothesis, sera and saliva samples collected from neonates infected with 116E-like (P[11]G9) strains in the maternity ward of the All India Institute of Medical Sciences (AIIMS) hospital in New Delhi were tested for neutralizing antibodies against common RV strains and those infecting newborns and these titers were compared with those of newborns who did not become infected (controls). The infected neonates had significantly lower levels of cord blood neutralizing antibodies to 116E than the controls, suggesting that immunity to neonatal RV infection is acquired transplacentally through maternal antibodies. Further, this study confirmed the immunogenicity of the AIIMS neonatal strain 116E, a vaccine candidate, in its ability to evoke a potent RV-specific immunoglobulin A and neutralizing antibody response in serum and saliva among the infected babies. Our findings have important implications for the development of an effective RV vaccine. In India, where G9 strains are common in the community, the use of 116E as a vaccine, together with the rhesus tetravalent vaccine, may provide a broader protection against all the circulating RV serotypes, including serotype G9, which is not represented in the current rhesus RV tetravalent vaccine (G1-G4).

Unusual diversity of human rotavirus G and P genotypes in India

Between April and December 1993, we determined P and G genotypes of group A rotavirus strains obtained from children admitted to diarrhea treatment centers in five Indian cities. From a total of 63 rotavirus-positive specimens, we identified 10 different strains with five different G genotypes and four distinct P types by using reverse transcription-PCR. The common worldwide strains G1P8, G2P4, G3P8, and G4P8 were underrepresented among Indian children (33%), whereas strains of P type 6 (G1P6, G2P6, G3P6, G4P6, and G9P6), which primarily infect asymptomatic newborns but are rare in children with diarrhea were common in India (43%). Of these, G9P6, a strain not previously reported to be found in children with diarrhea, was the most prevalent (22%). Eleven percent of the strains were nontypeable, and another 11% of the specimens had mixed infections. Using digoxigenin-labeled, genotype-specific hybridization probes, we confirmed all G9 strains and mixed infections tested and identified three nontypeable strains (one G9 and two P8). The epidemiological significance of G9 rotavirus strains, if confirmed in other settings, may have important implications for vaccine development.