Biomedical subjects
Publications and source records attributed to V H Rodrigues.
In the 1:1 adduct formed between L-phenylalanine and 4-nitrophenol [alternative IUPAC name: (2S)-2-ammonio-3-phenylpropanoate-4-nitrophenol (1/1)], C9H11NO2.C6H5NO3, the L-phenylalanine molecule is in the zwitterionic state. The overall structure is stabilized via strong hydrogen bonding between polar zones and van der Waals interactions between non-polar zones, which alternate with the polar zones.
The title compound, tetraaquabis(hydrogen L-malato)strontium(II) dihydrate, [Sr(C4H5O5)2(H2O)4].2H2O, is a new non-linear optical semi-organic material with a second harmonic generation efficiency approximately 3.5 times greater than that of potassium dihydrogen phosphate. The malate anions are interconnected through directional O-H...O hydrogen bonding, in a head-to-tail arrangement, creating extended anionic chains along [001]. Neighbouring parallel chains are crosslinked by water molecules, resulting in a three-dimensional architecture. The Sr2+ ion is coordinated by eight O atoms. This material is a new candidate for non-linear optical applications since the crystals are stable and easy to grow.
The title compound, C2H6NO2+.C2Cl3O2-, crystallizes in the P4(1) space group with two glycinium cations and two trichloroacetate anions in the asymmetric unit. The glycinium cations have nearly Cs point-group symmetry which is only broken by the H atoms of the amine group. The trichloroacetate anions show typical bond lengths and angles, one of the trichloromethyl groups being disordered. Chains of alternating anions and cations run along the c axis. Within these chains, consecutive anion-cation pairs are bound via strong hydrogen bonds involving the carboxylate anions and the carboxyl or amine groups of the cations. Weaker hydrogen bonds bind neighbouring chains together.
In the title compound, C(2)H(6)NO(2)(+).C(2)F(3)O(2)(-), the main N-C-COOH skeleton of the glycinium cation is almost perfectly planar. The trifluoroacetate anion has a staggered conformation with typical bond distances and angles. The CF(3) group is slightly disordered. The structure is stabilized by an extensive network of strong O-H.O hydrogen bonds and weaker N-H.O bonds.
The title compound, C5H12NO2+*C2F3O2- or BET+*CF3COO- [BET is trimethylglycine (betaine); IUPAC: 1-carboxy-N,N,N-trimethylmethanaminium inner salt], contains pairs of betainium and trifluoroacetate ions forming a dimer bridged by a strong hydrogen bond between the carboxyl and carboxylate groups of the two ions. The molecular symmetry of the cation is close to Cs, with protonation occurring at the carboxy O atom positioned anti to the N atom. The trifluoroacetate anions are disordered over two positions. In one, the conformation of the CF3 group is staggered with respect to the carboxylate group, in the other, it is close to an eclipsed conformation. The sole hydrogen bond present in the structure is the strong O-H...O bond between the anion and the cation.
The purpose of this study was to evaluate gemcitabine plus paclitaxel in heavily pretreated patients with metastatic breast cancer (MBC). Patients with MBC with second or third relapse to anthracycline-containing regimens received a 3-hour infusion of paclitaxel 175 mg/m2 on day 1, and gemcitabine 1.0 g/m2 on days 1, 8, and 15, every 28 days. Because of unacceptable thrombocytopenia seen in the first 5 patients, the gemcitabine schedule was changed to days 1 and 8 (G-1,8) for the remainder of the study, every 21 days. Twenty-nine patients (median age, 46 years; range, 32-68 years) received 137 cycles (median: 4 per patient). The regimen was well tolerated. World Health Organization grades III and IV thrombocytopenia were observed in 5 (18.5%) of the first 27 cycles (G-1,8,15), and in 6 (5.4%) of the 110 subsequent cycles (G-1,8)--p = 0.04 for the difference between schedules. Five patients had grade I and two had grade III neuropathy. Eight patients had grade III neutropenia, two had grade IV neutropenia associated with fever (G-1,8,15), and eight had grades I and II myalgia and fatigue. There were 16 (55%) objective responses (95% CI 36-73%); 5 (17%) complete responses, 11 (38%) partial responses (95% CI 3-30% and 19-56%, respectively), and 6 (20.5%) patients with stable disease. Median response duration was 8 months (range, 4-26 months). Median overall survival was 12 months (range, 4-28+ months), and 1-year and 2-year survival rates were 45% and 30%, respectively. This phase II study demonstrated a manageable toxicity profile with the gemcitabine day 1, 8 schedule in combination with paclitaxel and significant and promising activity in heavily pretreated patients with MBC. A confirmatory phase III trial is warranted.
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In the title compound, C(4)H(10)NO(2)(+).C(2)F(3)O(2)(-), the main N-C-COOH skeleton of the protonated amino acid is nearly planar. The C=O/C-N and C=O/O-H bonds are syn and the two methyl groups are gauche to the methylene H atoms. The conformation of the cation in the crystal is compared to that given by ab initio calculations (Hartree-Fock, self-consistent field molecular-orbital theory). The trifluoroacetate anion has the typical staggered conformation with usual bond distances and angles. The cation and anion form dimers through a strong O-H.O hydrogen bond which are further interconnected in infinite zigzag chains running parallel to the a axis by N-H.O bonds. Weaker C-H.O interactions involving the methyl groups and the carboxy O atoms of the cation occur between the chains.
In a phase II trial, 29 patients with anthracycline-pretreated or anthracycline-resistant metastatic breast cancer in whom anthracycline-containing first- or second-line chemotherapy failed received combination paclitaxel (Taxol)/gemcitabine (Gemzar). The initial regimen of paclitaxel at 175 mg/m2 on day 1 and gemcitabine at 1,000 mg/m2 on days 1, 8, and 15 of a 28-day cycle was given to five patients for a total of 27 cycles. The regimen resulted in excessive thrombocytopenia and was subsequently changed to gemcitabine at the same dose on days 1 and 8 of a 21-day cycle, with study treatment being given for a maximum of eight cycles. This regimen was well tolerated. Further evaluation of this regimen in minimally and heavily pretreated patients with advanced breast cancer is warranted.
The title compound, C(3)H(8)NO(2)(+).C(2)F(3)O(2)(-), crystallizes in space group C2/c. The main N-C-COOH skeleton of the protonated sarcosine molecule is almost perfectly planar. The trifluoroacetate anion has a staggered conformation and typical bond distances and angles. The CF(3) group is probably slightly disordered. The structure is stabilized by an extensive network of strong O-H.O hydrogen bonds and weaker N-H.O bonds.
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