TRPA1 and TRPV4 activation in human odontoblasts stimulates ATP release.

The mechanism of pain in dentine hypersensitivity is poorly understood but proposed to result from the activation of dental sensory neurons in response to dentinal fluid movements. Odontoblasts have been suggested to contribute to thermal and mechanosensation in the tooth via expression of transient receptor potential (TRP) channels. However, a mechanism by which odontoblasts could modulate neuronal activity has not been demonstrated. In this study, we investigated functional TRP channel expression in human odontoblast-like cells and measured ATP release in response to TRP channel activation. Human immortalized dental pulp cells were driven toward an odontoblast phenotype by culture in conditioned media. Functional expression of TRP channels was determined with reverse transcription polymerase chain reaction and ratiometric calcium imaging with Fura-2. ATP release was measured using a luciferin-luciferase assay. Expression of mRNA for TRPA1, TRPV1, and TRPV4 but not TRPM8 was detected in odontoblasts by reverse transcription polymerase chain reaction. Expression of TRPV4 protein was detected by Western blotting and immunocytochemistry. The TRPA1 agonists allyl isothiocyanate and cinnamaldehyde and the TRPV4 agonist GSK1016790A caused a concentration-dependent increase in intracellular Ca(2+) concentration that was inhibited by the selective antagonists HC030031, AP18, and HC067047, respectively. In contrast, exposure to the TRPV1 agonist capsaicin or the TRPM8 agonist icilin had no effect on intracellular Ca(2+) concentration. Treatment with allyl isothiocyanate, cinnamaldehyde, or GSK1016790A caused an increase in ATP concentration in culture medium that was abolished by preincubation with TRP channel antagonists. These data demonstrate that activation of TRPA1 and TRPV4 channels in human odontoblast-like cells can stimulate ATP release. We were unable to confirm the presence of thermosensitive TRPV1 and TRPM8 that has previously been reported in odontoblasts.

Synthesis, crystal structures and spectroscopy of meclofenamic acid and its metal complexes with manganese(II), copper(II), zinc(II) and cadmium(II). Antiproliferative and superoxide dismutase activity.

Some new complexes of meclofenamic acid (N-(2,6-dichloro-m-tolyl)anthranilic acid), Hmeclo (1), with potentially interesting biological activities are described. Complexes [Mn(meclo)(2)] (2), [Cu(meclo)(2)(H(2)O)(2)] (3), [Zn(meclo)(2)(H(2)O)(2)] (4) and [Cd(meclo)(2)(H(2)O)(2)] (5) were prepared and structurally characterized by means of vibrational, electronic and (1)H and (13)C NMR spectroscopies. The crystal structure of complexes [Cu(4)(meclo)(6)(OH)(2)(DMSO)(2)]2DMSO (3a) and [Cd(meclo)(2)(DMSO)(3)] (5a) have been determined by X-ray crystallography. Complex (3a) is a centrosymmetric tetramer built up around the planar cyclic Cu(2)(OH)(2) unit. Complex 5a is mononuclear seven-coordinated complex with the meclofenamato ligand behaving as a bidentate deprotonated chelating ligand. Intra and intermolecular hydrogen bonds stabilize these two structures, while the crystal packing is determined by π-π and C-H--π interactions. Meclofenamic acid and its metal complexes have been evaluated for antiproliferative activity in vitro against the cells of three human cancer cell lines, MCF-7 (breast cancer cell line), T24 (bladder cancer cell line), and A-549 (non-small cell lung carcinoma), and a mouse fibroblast L-929 cell line. Complex 5 exhibits the highest selectivity against MCF-7 and 4 shows the highest selectivity against T-24. Complexes 2-5 were found to be more potent cytotoxic agents against T-24 and complex 5 against MCF-7 cancer cell lines than the prevalent benchmark metallodrug, cis-platin. The superoxide dismutase activity was measured by the Fridovich test which showed that complex [Cu(meclo)(2)(H(2)O)(2)] is a good superoxide scavenger.

Diorganotin complexes of a thiosemicarbazone, synthesis: properties, x-ray crystal structure, and antiproliferative activity of diorganotin complexes.

The synthesis and spectral characterization of novel diorganotin complexes with 3-hydroxypyridine-2-carbaldehyde thiosemicarbazone, H(2)L(1), [SnMe(2)(L)] (2), [SnBu(2)(L)] (3), and [SnPh(2)(L)] (4) are reported. The single-crystal X-ray structure of complex [SnPh(2)(L)(DMSO)] (5) shows that the ligand is doubly deprotonated and is coordinated as tridentate ligand. The six coordination number is completed by two carbon atoms of phenyl groups. There are two similar monomers 5a (Sn1) and 5b (Sn51) in the asymmetric unit. The monomers 5a and 5b are linked through intermolecular hydrogen bonds of N-H-O and C-H-S type. C-H --> pi, intermolecular interactions, intra- and intermolecular hydrogen bonds stabilize this structure and leads to aggregation and a supramolecular assembly. The IR and NMR ((1)H, (13)C and (119)Sn) spectroscopic data of the complexes are reported. The in vitro cytotoxic activity has been evaluated against the cells of three human cancer cell lines: MCF-7 (human breast cancer cell line), T-24 (bladder cancer cell line), A-549 (nonsmall cell lung carcinoma) and a mouse L-929 (a fibroblast-like cell line cloned from strain L). Compounds 1, 3, and 4 were found active against all four cell lines. Selectivity was observed for complexes 3 and 4 which were found especially active against MCF-7 and T-24 cancer cell lines.

Organotin Compound Derived from 3-Hydroxy-2-formylpyridine Semicarbazone: Synthesis, Crystal Structure, and Antiproliferative Activity.

The novel diphenyltin(IV) compound [Ph(2)(HyFoSc)Sn] (2), where H(2)HyFoSc (1) is 3-hydroxy-2-formylpyridine semicarbazone, was prepared and characterized by vibrational and NMR ((1)H, (13)C) spectroscopy. The structure of [Ph(2)(HyFoSc)Sn] was confirmed by single-crystal X-ray crystallography. The doubly deprotonated ligand is coordinated to the tin atom through the enolic-oxygen, the azomethine-nitrogen, and phenolic-oxygen, and so acts as an anionic tridentate ligand with the ONO donors. Two carbon atoms complete the fivefold coordination at the tin(IV) center. Intermolecular hydrogen bonding, C-H --> pi, and pi --> pi interactions combine to stabilize the crystal structure. Compounds 1 and 2 have been evaluated for antiproliferative activity in vitro against the cells of three human tumor cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A549 (nonsmall cell lung carcinoma), and a mouse fibroblast L-929 cancer cell line.

Zinc(II) complexes of 2-acetyl pyridine 1-(4-fluorophenyl)-piperazinyl thiosemicarbazone: Synthesis, spectroscopic study and crystal structures - potential anticancer drugs.

2-Acetyl pyridine thiosemicarbazone containing an 1-(4-fluorophenyl)-piperazinyl ring incorporated at N(4)-position, HAcPipPheF (1) and the zinc(II) complexes [Zn(AcPipPheF)(2)] (2) and [Zn(OAc)(AcPipPheF)](2) (3) have been prepared and structurally characterized by means of vibrational and NMR ((1)H and (13)C) spectroscopy. The crystal structures of the compounds 1-3 have been determined by X-ray crystallography. The metal coordination geometry of [Zn(AcPipPheF)(2)] is described as distorted octahedral configuration in a trans-N-cis-N-cis-S configuration. In [Zn(OAc)(AcPipPheF)](2) one of the acetato group exhibits monoatomic bridge and the other bridges in a bidentate manner. The zinc(1) metal ion is coordinated in a distorted octahedral configuration while the metal coordination of Zn(2) is described as distorted square pyramidal. Biomedical studies revealed that, compounds 1-3 displayed potent anticancer activity. The antiproliferative activity of 1-3 was found to be considerably stronger than that of cis-platin. The IC(50) values range from 26 to 90nM, against all cell lines tested, while for cis-platin the IC(50) values range from 2 to 17microM and for the zinc salt, ZnCl(2), the IC(50) values range from 81 to 93microM. The complex 3 shows the highest activity against all four cancer cell lines and the highest selectivity against K562 and MDA-MB-453 cancer cell lines. The compounds inhibited tumor cell proliferation by arresting the cell cycle progression at the S phase.

Anti-inflammatory, antiproliferative, and radical-scavenging activities of tolfenamic acid and its metal complexes.

Some new complexes of tolfenamic acid (=2-[(2-methyl-3-chlorophenyl)amino]benzoic acid; Htolf) with potentially interesting biological activities are described. The complexes [Mn(tolf)(2)(H(2)O)(2)], [Co(tolf)(2)(H(2)O)(2)], [Ni(tolf(2)(H(2)O)(2)], [Cu(tolf)(2)(H(2)O)](2), and [Zn(tolf)(2)(H(2)O)] were prepared by the reaction of tolfenamic acid, a potent anti-inflammatory drug, with metal salts. The radical-scavenging activities of the complexes were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging assay. Their ability to inhibit soybean lipoxygenase, beta-glucuronidase, and trypsin-induced proteolysis was studied. Their inhibitory effects on rat paw edema induced by carrageenin was studied and compared with those of tolfenamic acid. The complex [Zn(tolf)(2)(H(2)O)] exhibited the strongest in vivo inhibitory effect at 0.1 mm/kg Body Weight (BW; 93.0+/-0.9%), superior than the inhibition induced by tolfenamic acid at the same molar dose (76.0+/-0.9%). Tolfenamic acid and its metal complexes have been evaluated for antiproliferative activity in vitro against the cells of three human cancer cell lines, MCF-7 (breast cancer cell line), T24 (bladder cancer cell line), and A-549 (non-small cell lung carcinoma), and a mouse fibroblast L-929 cell line. The complexes [Mn(tolf)(2)(H(2)O)(2)] and [Cu(tolf)(2)(H(2)O)](2) have shown selectivity against T24 cell line. The IC(50) values of these two complexes against T24 cancer cell lines are in a micromolar range similar or better to that of the antitumor drug cisplatin.

Organotin meclofenamic complexes: Synthesis, crystal structures and antiproliferative activity of the first complexes of meclofenamic acid - novel anti-tuberculosis agents.

The complexes [Me(2)(Meclo)SnOSn(Meclo)Me(2)](2) (2) and [Ph(3)Sn(Meclo)] (3) where HMeclo is meclofenamic acid, N-(2,6-dichloro-m-tolylanthranilic acid)], have been prepared and structurally characterized by means of vibrational, (1)H and (13)C NMR spectroscopies. The crystal structure of complexes (2) and (3) have been determined by X-ray crystallography. Three distannoxane rings are present to the dimeric tetraorganodistannoxane of planar ladder arrangement of (2). The structure is centro symmetric and features a central rhombus Sn(2)O(2) unit two additional tin atoms linked at the oxygen atoms. Five- and six-coordinated tin centers are present in the dimer distannoxane. X-ray analysis of (3) revealed a penta-coordinated structure containing Ph(3)Sn coordinated to the chelated carboxylato group. The polar imino hydrogen atom participates in intra-molecular hydrogen bonds. Complexes (2) and (3) are self-assembled via pi-->pi, C-H-pi, stacking interactions and intra-molecular hydrogen bonds. Meclofenamic acid and [Ph(3)Sn(Meclo)] have been evaluated for antiproliferative activity in vitro against three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse L-929 (a fibroblast-like cell line cloned from strain L). The [Ph(3)Sn(Meclo)] complex exhibited high cytotoxic activity against all the cancer cell lines. Meclofenamic and [Ph(3)Sn(Meclo)] were tested for anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv. The [Ph(3)Sn(Meclo)] complex was found to be a promising anti-mycobacterial lead compound, displaying high activity against M. tuberculosis H37Rv.

In vitro and in vivo antitumor activity of platinum(II) complexes with thiosemicarbazones derived from 2-formyl and 2-acetyl pyridine and containing ring incorporated at N(4)-position: synthesis, spectroscopic study and crystal structure of platinum(II) complexes with thiosemicarbazones, potential anticancer agents.

Reactions of thiosemicarbazones of 2-formyl and 2-acetyl pyridine and containing an azepane ring (hexamethyleneiminyl ring) incorporated at N(4)-position, HL(1) (1) and HL(2) (2) with platinum(II) afforded the complexes, [Pt(L(1))Cl] (3) and [Pt(L(2))Cl] (4). Characterization of the compounds was accomplished by means of elemental analysis and spectroscopic techniques NMR, UV-vis and IR spectroscopy. The single-crystal X-ray structure of complex [Pt(L(2))Cl] (4) shows that the ligand monoanion coordinates in a planar conformation to the metal via the pyridyl N atom, the imine-N atom, and thiolato S-atom. Compounds 1-4 have been evaluated for antiproliferative activity in vitro against three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse L-929 (a fibroblast-like cell line cloned from strain L). Ligand 2 exhibited high activity as anticancer agent against all four cancer cell lines, while ligand 1 exhibited selectivity against MCF-7, L-929 cell lines and complex 4 against A-549, T-24 cancer cell lines. Also, the acute toxicity and antitumor activity were evaluated on leukemia P388-bearing mice. Complex 3 afforded five to six cures against leukemia P388. The in vivo results of the antitumor activity show the two platinum complexes as very effective chemotherapeutic antileukemic agents.

Anti-oxidant, in vitro, in vivo anti-inflammatory activity and antiproliferative activity of mefenamic acid and its metal complexes with manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II).

Some new complexes of mefenamic acid with potentially interesting biological activity are described. The complexes of mefenamic acid [Mn(mef)(2)(H(2)O)(2)], 1, [Co(mef)(2)(H(2)O)(2)], 2, [Ni(mef)(2)(H(2)O)(2)], 3, [Cu(mef)(2)(H(2)O)](2), 4 and [Zn(mef)(2)], 5, were prepared by the reaction of mefenamic acid, a potent anti-inflammatory drug with metal salts. Optical and infrared spectral data of these new complexes are reported. Monomeric six-coordinated species were isolated in the solid state for Mn(II), Ni(II) and Co(II), dimeric five-coordinated for Cu(II) and monomeric four-coordinated for Zn(II). In DMF or CHCl(3) solution the coordination number is retained and the coordinated molecules of water are replaced by solvent molecules. The anti-oxidant properties of the complexes were evaluated using the 1,1-diphenyl-2-picrylhydrazyl, DPPH, free radical scavenging assay. The scavenging activities of the complexes were measured and compared with those of the free drug and vitamin C. We have explored their ability to inhibit soybean lipoxygenase, beta-glucuronidase and trypsin- induced proteolysis. The complex [Mn(mef)(2)(H(2)O)(2)] exhibits the highest antioxidant activity and the highest inhibitory effect against the soybean lipogygenase (LOX), properties that are not demonstrated by mefenamic acid. Their inhibitory effects on rat paw edema induced by Carrageenan was studied and compared with those of mefenamic acid. The complex [Zn(mef)(2)] exhibited a strong inhibitory effect at 0.1 mmol/Kg B.W. (81.5 +/- 1.3% inhibition), superior to the inhibition induced by mefenamic acid at the same dose (61.5 +/- 2.3% inhibition). Mefenamic acid and its metal complexes have been evaluated for antiproliferative activity in vitro against the cells of three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse fibroblast L-929 cell line. The copper(II) complex displays against T24, MCF-7 and L-929 cancer cell lines, IC(50) values in a microM range similar to that of the antitumor drug cis-platin and they are considered for further stages of screening in vitro and/or in vivo as agents with potential antitumor activity.

Zinc(II) complexes derived from pyridine-2-carbaldehyde thiosemicarbazone and (1E)-1-pyridin-2-ylethan-1-one thiosemicarbazone. Synthesis, crystal structures and antiproliferative activity of zinc(II) complexes.

The complexes [ZnCl(2)(HFoTsc)xH(2)O], [Zn(FoTsc)(2)], [ZnCl(2)(HAcTsc)xH(2)O] and [Zn(AcTsc)(2)], where HFoTsc and HAcTsc is pyridine-2-carbaldehyde thiosemicarbazone and (1E)-1-pyridin-2-ylethan-1-one thiosemicarbazone respectively, have been prepared and structurally characterized by means vibrational, and NMR ((1)H and (13)C) spectroscopy. The crystal structures of the complexes [ZnCl(2)(HFoTsc)xH(2)O], [Zn(AcTsc)(2)] and [ZnCl(2)(HAcTsc)xH(2)O] have been determined by X-ray crystallography. The metal co-ordination geometry of [ZnCl(2)(HFoTsc)xH(2)O] and [ZnCl(2)(HAcTsc)xH(2)O] is described as distorted square pyramidal and the two complexes are self-assembled via pi-->pi stacking interactions and intermolecular hydrogen bonds. In these two cases molecular recognition of the hydrogen bonds leads to aggregation and a supramolecular assembly of infinite two-dimensional network. The metal co-ordination geometry of [Zn(AcTsc)(2)] is described as distorted octahedral configuration in a trans-N(2)-cis-N(1)-cis-S configuration. HFoTsc and HAcTsc and the zinc complexes have been evaluated for antiproliferative activity in vitro against the cells of two human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line) and a mouse fibroblast L-929 cell line. The cytotoxic activity shown by these compounds indicates that coupling of HFoTsc and HAcTsc to Zn(II) metal center result in metallic complexes with important biological properties since they display IC(50) values in a microM range similar to or better than that of the antitumor drug cis-platin and are considered as agents with potential antitumor activity candidates for further stages of screening in vitro and/or in vivo.

Synthesis and spectroscopic study of copper(II) and manganese(II) complexes with pipemidic acid.

The interaction of copper(II) and manganese(II) with pipemidic acid, Hpipem, afforded the complexes [Cu(pipem)(2)(H(2)O)] x 2H(2)O, 1 and [Mn(pipem)(2)(H(2)O)], 2. The new complexes have been characterised by elemental analyses, infrared, UV-vis and X-band EPR spectroscopy in the temperature range from 4 to 300 K. The monoanion, pipem, exhibits O,O ligation through the carbonyl and carboxylato oxygen atoms. Five coordinate square-pyramid configuration has been proposed for 1 and 2, and the fifth apical position is occupied by a coordinated water molecule.

Preparations and spectroscopic studies of organotin complexes of diclofenac.

The reactions of the potent and widely used anti-inflammatory drug diclofenac, HL, with diorganotin(IV) oxides were studied. The dimeric tetraorganodistannoxane complexes [Me(2)LSnOSnLMe(2)](2), [Bu(2)LSnOSnLBu(2)](2), [Ph(2)LSnOSnLPh(2)](2) and the dibutyltin complex [Bu(2)SnL(2)], have been prepared and structurally characterized in the solid state by means of vibrational and 119Sn Mössbauer spectroscopy. Determination of lattice dynamics by temperature-dependent 119Sn Mössbauer spectroscopy. From the variable-temperature Mössbauer effect, the Debye temperature was determined. The complexes have been characterized in solution by NMR (1H and 13C) spectroscopy. Vibrational, Mössbauer, and NMR data are discussed in terms of the proposed structures.

Binuclear copper(II) complexes of tolfenamic: synthesis, crystal structure, spectroscopy and superoxide dismutase activity.

The synthesis and characterization of copper(II) complexes with a potent non-steroidal anti-inflammatory drug, tolfenamic acid, Htolf, with formula [Cu(tolf)(2)L](2) (where L is H(2)O or DMF, N,N-dimethylformamide) were investigated. The crystal and molecular structure of [Cu(tolf)(2)(DMF)](2) was reported. Crystallographic data are as follows: monoclinic system, space group P2(1)/n with cell constants a=9.068(2) A, b=14.514(3) A, c=22.826(4) A, V=2948.9(10) A(3) and Z=2. The crystal structure consists of binuclear, quadruply bridged neutral molecule with a Cu-Cu bond length of 2.6075(19) A. The complex is self-assembled via C-H-pi intermolecular stacking interactions. Spectroscopic and electrochemical studies were reported. The superoxide dismutase activity is measured and compared with those of superoxide dismutase enzyme, SOD, the free ligand and related copper complexes with non-steroidal anti-inflammatory drugs, NSAIDs. IC(50) value was measured by the Fridovich test (1.97+/-0.17 microM), which showed that [Cu(tolf)(2)L](2) is a good superoxide scavenger.

Platinum(II) and palladium(II) complexes with 2-acetyl pyridine 4N-ethyl thiosemicarbazone able to overcome the cis-platin resistance. Structure, antibacterial activity and DNA strand breakage.

The reactions of Pd(II) and Pt(II) with 2-Acetyl Pyridine N(4)-Ethyl-Thiosemicarbazones, HAc4Et and 2-Acetyl Pyridine N(4)-1-(2-pyridyl)-piperazinyl Thiosemicarbazone, HAc4PiPiz and 2-Formyl Pyridine N(4)-1-(2-pyridyl)-piperazinyl Thiosemicarbazone, HFo4PiPiz afforded the complexes, [Pd(Ac4Et)], 1, [Pd(HAc4Et)2]Cl2, 2 and [Pd(Ac4Et)2], 3 [Pt(Ac4Et)], 4, [Pt(HAc4Et)2]Cl2, 5, [Pt(Ac4Et)2], 6 and [Pd(Fo4PipePiz)Cl], 7, [Pd(Fo4PipePiz)2], 8, [Pd(Ac4PipePiz)Cl], 9 and [Pd(Ac4PipePiz)2], 10. The crystal structure of the complex [Pt(Ac4Et)2], 6 has been solved. The platinum(II) atom is in a square planar environment surrounded by two cis nitrogen atoms and two cis sulfur atoms. The ligands are not equivalent, one being tridentate with (N,N,S) donation, the other being monodentate using only the sulfur atom to coordinate to the metal. The tridentate ligand shows a Z, E, Z configuration while the monodentate ligand shows an E, E, Z. Inter-molecular hydrogen bonds stabilize the structure, while the crystal packing is determined by pi-pi, and Pt-C interactions. The antibacterial effect of Pd(II) and Pt(II) complexes were studied in vitro. The complexes were found to have effect on Gram(+) bacteria, while the same complexes showed no bactericidal effect on Gram(-) bacteria. The effect of the Pd(II) and Pt(II) complexes on the in vitro DNA strand breakage was studied by agarose gel electrophoresis. The complexes 1-6 were found to exhibit a cytotoxic potency in a very low micromolar range and to be able to overcome the cisplatin resistance of A2780/Cp8 cells.

Indoor radon levels and influencing factors in houses of Patras, Greece.

Measurements of indoor radon concentrations were performed in 28 low-rise houses and 30 apartments in Patras area from December 1996 to November 1997, using nuclear track detectors. The investigation was focused on the effects of season and floor number, as well as on the existence of a basement in low-rise houses on indoor radon levels. It was found that the differences in mean radon concentrations between adjacent seasons, in a number of 61 selected sampling sites distributed in 28 houses, were statistically significant. As expected, a maximum was found in winter and a minimum in summer. The differences in mean radon concentration on different floors of the same houses were also statistically significant and followed a linear decrease from underground to 2nd floor. In addition, indoor radon concentrations in the ground floor were found to be influenced by the existence or not of a basement. The average annual radon concentration was found to be 41 Bq m(-3) for the houses, 28 Bq m(-3) for the apartments and 38 Bq m(-3) for all the dwellings. These values lead to an average effective dose equivalent of 1.1, 0.7 and 0.9 mSv y(-1), respectively. Residents living on the underground in low-rise houses, during winter, where the average effective dose equivalent is 2.1 mSv y(-1), attain the higher risk.

Structure of bis(2-acetylpyridine 3-hexamethyleneiminylthiosemicarbazonato) palladium II, a potential antitumor complex.

The crystal structure of the potential antitumor complex bis(2-acetyppyridine 3-hexamethyleneiminylthiosemicarbazonato)palladium(II) has been solved. The palladium(II) atom is in a square planar environment surrounded by two cis nitrogen atoms and two cis sulfur atoms. The ligands are not equivalent, one being tridentate with (N,N,S) donation, the other being monodentate using only the sulfur atom to coordinate to the metal. The tridentate ligand shows a Z, E, Z configuration while the monodentate ligand shows an E, E, Z. Intermolecular hydrogen bonds stabilize the structure, while the crystal packing is determined by Pd-C, Pd-pi, C-H-pi and pi-pi interactions.

Developmental and gender differences in the relationship of behavior pattern to heart rate reactivity between two teenage samples.

The Type A Behavior Pattern was assessed for 122 teenagers from two age-groups. Subjects had their heart rate measured during rest and presentation of a mental arithmetic stressor under timed and competitive conditions. Data were analyzed to determine whether sex, age, task performance, and behavior pattern predicted the degree of heart rate reactivity shown by these children. Although there were no significant main effects for behavior pattern, sex, or age, there was a significant interaction among age, sex, and behavior pattern. It is suggested that the two age groups of teenagers sampled here differ in the relationships they show between behavior pattern and heart rate reactivity. This result challenges some previous assumptions with regard to the homogeneity of teenagers on this issue.