Synthesis, structural characterization, cytotoxic properties and DNA binding of a dinuclear copper(II) complex

In this study a novel dinuclear copper(II) complex with adenine and phenanthroline has been synthesized and its structure determined by single crystal X-ray diffraction. In the dinuclear complex [Cu₂(μ-adenine)₂(phen)₂(H2O)2](NO3)4·0.5H2O (phen=1,10-phenanthroline) (1) the two Cu(II) centres exhibit a distorted square pyramidal coordination geometry linked by two nitrogen donors from adenine bridges leading to a Cu-Cu distance of 3.242(3)Å. Intramolecular and intermolecular π⋯π interactions as well as an H-bonding network were observed. The antitumor capacity of the complex has been tested in vitro against human cancer cell lines, cervical carcinoma (HeLa) and colorectal adenocarcinoma (Caco-2), by metabolic tests, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as reagent. The complex 1 has remarkable low IC50 values of 0.87±0.06μM (HeLa) and 0.44±0.06μM (Caco-2), when compared with values for cisplatin against the same cell lines. The interaction of complex 1 with calf thymus DNA (CT DNA) was further investigated by absorption and fluorescence spectroscopic methods. A binding constant of 5.09×10(5)M(-1) was obtained from UV-vis absorption studies.

A thermal porosimetry method to estimate pore size distribution in highly porous insulating materials

Standard pore size determination methods such as mercury porosimetry, nitrogen sorption, microscopy, or x-ray tomography are not always applicable to highly porous, low density, and thus very fragile materials. For this kind of materials, a method based on thermal characterization is proposed. Indeed, the thermal conductivity of a highly porous and insulating medium is significantly dependent on the thermal conductivity of the interstitial gas that depends on both gas pressure and size of the considered pore (Knudsen effect). It is also possible to link the pore size with the thermal conductivity of the medium. Thermal conductivity measurements are realized on specimens placed in an enclosure where the air pressure is successively set to different values varying from 10(-1) to 10(5) Pa. Knowing the global porosity ratio, an effective thermal conductivity model for a two-phase air-solid material based on a combined serial-parallel model is established. Pore size distribution can be identified by minimizing the sum of the quadratic differences between measured values and modeled ones. The results of the estimation process are the volume fractions of the chosen ranges of pore size. In order to validate the method, measurements done on insulating materials are presented. The results are discussed and show that pore size distribution estimated by the proposed method is coherent.

Stepwise hapticity changes in sequential one-electron redox reactions of indenyl-molybdenum complexes: combined electrochemical, ESR, X-ray, and theoretical studies

Reduction of the dication [(eta5-Ind)(Cp)Mo[P(OMe)3]2]2+ (1(2+)) and oxidation of the neutral complex (eta3-Ind)(Cp)Mo[P(OMe)3]2 (1) proceed through a one-electron intermediate, 1+. The structures of 1(2+) and 1 have been determined by X-ray diffraction studies, which show the slip-fold distortion angle, Omega, of the indenyl ring increasing from 4.1 degrees in 1(2+) to 21.7 degrees in 1. Cyclic voltammetry and bulk electrolysis were employed to define the thermodynamics and heterogeneous charge-transfer kinetics of reactions 1(2+) + e(-) <==> 1+ and 1+ + e(-) <==> 1: DeltaE1/2 = 113 mV in CH3CN and 219 mV in CH2Cl2/0.1 M [NBu4][PF6]; k(s) = 0.4 cm x s(-1) for 1(2+)/1+ couple, 1.0 cm x s(-1) for 1+/1 couple in CH3CN. ESR spectra of 1+ displayed a surprisingly large hyperfine splitting (7.4 x 10(-4) x cm(-1)) from a single 1H nucleus, and spectra of the partially deuterated indenyl analogue confirmed assignment of a(H) to the H2 proton of the indenyl ring. The related eta5 18-electron complexes [(eta5-Ind)(Cp)Mo(dppe)]2+ (2(2+)) (dppe = diphenylphosphinoethane) and (eta5-Ind)(Cp)Mo(CN)2 (3) may also be reduced in two successive one-electron steps; ESR spectra of the radicals 2+ and 3- showed a similarly large a(H2) (8.7 x 10(-4) and 6.4 x 10(-4) x cm(-1), respectively). Molecular orbital calculations (density functional theory, DFT, and extended Hückel, EH) predict metal-indenyl bonding in 1+ that is approximately midway between that of the eta5 and eta3 hapticities (e.g., Omega = 11.4 degrees ). DFT results show that the large value of a(H2) arises from polarization of the indenyl-H2 by both inner-sphere orbitals and the singly occupied molecular orbital (SOMO) of 1+. The measured ks values are consistent with only minor inner-sphere reorganizational energies being necessary for the electron-transfer reactions, showing that a full eta5/eta3 hapticity change may require only small inner-sphere reorganization energies when concomitant with a pair of stepwise one-electron-transfer processes. The indenyl ligand in 1+ is best described as donating approximately four pi-electrons to Mo by combining a traditional eta3 linkage with two "half-strength" Mo-C bonds.

Characterization and differentiation of ruthenium(II) complexes with 1,4,7-trithiacyclononane and nitrogen heterocycles by electrospray mass spectrometry

Electrospray ionization mass spectrometry (ESIMS) was used to characterize a series of new ruthenium(II) complexes with several nitrogen heterocycles and a common ligand: the crown thioether 1,4,7-trithiacyclononane, [9]aneS(3). ESIMS allows the easy identification of the [Ru(II)Cl([9]aneS(3))Y]X complexes, where Y is a bidentate nitrogen heterocycle and X is Cl(-) or PF(6)(-), through the formation of two diagnostic ions by fragmentation of the common ligand [9]aneS(3). Structures for these ions and mechanisms for their gas-phase formation are proposed based on data from product ion spectra.

[Blood neuronal specific enolase in newborns with perinatal asphyxia]

INTRODUCTION

Neuron-specific enolase (NSE) is a sensitive marker of brain injury after hypoxia or ischemia. There are few studies about its usefulness in asphyctic newborns.

OBJECTIVE

To study the correlation between blood NSE levels and neurological outcome in newborns with hypoxic ischemic encephalopathy.

PATIENTS AND METHODS

We have determined the blood values of NSE by radioimmunoassay in 25 asphyctic term-newborns with clinical encephalopathy (of mild, moderate and severe degree) and in 22 healthy term newborns (control group). Blood samples were obtained between 24 and 72 hours after birth in all neonates. Surviving infants were followed for a variable time (median: 3.5 years; range: 1-6) and the neurological status was determined.

RESULTS

NSE levels in the group of asphyctic neonates who died or developed neurological sequelae (n= 6; mean: 116.4 ng/ml; range: 42-226) were significantly higher than NSE values in the group of asphyctic neonates who were neurologically normal at follow-up (n= 19; mean: 21.3 ng/ml; range: 7.4-40), with p< 0.001. There were not differences between NSE values in the group of asphyctic neonates who developed neurologically normal and the control group (mean: 7.6 ng/ml; range: 10.3-28.3). Sensitivity and specificity of blood NSE as predictor of poor outcome were, respectively, 100% and 78%. The combined specificity for blood NSE together with a moderate/severe encephalopathy was 95%.

CONCLUSIONS

The presence of elevated NSE values in blood after perinatal asphyxia can be a sensitive indicator of conspicuous brain damage. The combined information provided by the severity of the encephalopathy together with the blood NSE values have shown a high predictive value for neurological outcome.

[Fraser syndrome: frequency in our environment and clinical-epidemiological aspects of a consecutive series of cases]

OBJECTIVE

Four major characteristics (cryptophthalmos, syndactyly, genital anomalies and affected siblings) and eight minor characteristics (alterations of the nose, ears, larynx, oral clefts, umbilical hernia, renal agenesis, skeletal anomalies and mental retardation) have been defined for the diagnosis of Fraser syndrome. The generally accepted criterion for the diagnosis is at least the presence of 2 major and one minor characteristic, or one major and four minor characteristics. The etiology of the syndrome is autosomal recessive and siblings are frequently affected.

PATIENTS AND METHODS

We show the characteristics of the 7 cases of Fraser syndrome identified in the consecutive series of 1,405,374 liveborn infants and 9,042 stillborn children surveyed by the Spanish Collaborative Study of Congenital Malformations (ECEMC) between April 1976 and March 1997.

RESULTS AND CONCLUSIONS

The minimal estimated frequency of Fraser syndrome is 0.43 per 100,000 liveborn infants and 11.06 per 100,000 stillbirths. As has been shown in other case studies, we have observed a wide clinical expression of this syndrome. At present it is possible to prenatally detect some of the characteristics of Fraser syndrome through ultrasound examination of eyes, digits and kidneys. Four out of the 7 cases we present here were gypsies and the frequency of the syndrome among liveborn gypsy infants is 129.3 times higher than among the non-gypsy population. Therefore, given that the frequency of the gene is higher in the gypsy population than in other ethic groups, it is recommended that a special search among gypsies for the identification of this and other autosomal recessive syndromes be performed.

[Brachmann-de-Lange syndrome in our population: clinical and epidemiological characteristics]

INTRODUCTION

We present the study of the clinical and epidemiological characteristics of Brachmann-de Lange syndrome in our population.

PATIENTS AND METHODS

In this study we present the analysis of 13 cases of Brachmann-de Lange syndrome identified among 24,696 infants with congenital defects registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC) between April 1976 and June 1996.

RESULTS

The minimum estimation of the prevalence in our population is 0.97 per 100,000 live births. We have epidemiologically confirmed the presence of intrauterine growth retardation and have observed that parental ages tend to be relatively young. We have observed a wide range of clinical expression of this syndrome. One hundred percent of our cases have limb reduction defects, followed in frequency by craniofacial alterations (84.62%), abnormal hair distribution (76.92%) and genital defects (69.23%). Upper limbs are predominantly affected and one case of diaphragmatic hernia is worth mentioning. We underline the importance of the differential diagnosis with Fryns'syndrome.

CONCLUSIONS

The cases studied correspond to the most severe form of the syndrome, reason for which the prevalence is a minimal estimate. However, the mild forms of the syndrome are more frequent and it is important to consider that the face, especially the form of the eyebrow, could be a good guide for the diagnosis of mild forms of the syndrome.

Description of the characteristics of cases with noncontiguous neural tube defects identified in a series of consecutive births

Van Allen et al. [(1973) Am. J. Med. Genet. 47:723-743] provided evidence for multisite closure of the neural tube in humans. Reynolds et al. [(1995) Proceedings of the Greewood Genetic Center 14:70-71] and Seller [(1995) J. Med. Genet. 32:205-207] described 13 and seven cases of noncontiguous neural tube defects (NTDs) respectively and concluded that the presence of noncontiguous NTDs cannot be explained on the basis of the model of a single initiation site with bidirectional closure. Here we present a series of 14 consecutive infants with noncontiguous NTDs, describing their characteristics. These show that noncontiguous NTDs are clinically heterogeneous, may have differences in sex ratio, and could have causal heterogeneity. The different combinations of closure failure defects have shown proportions in our population that are different from those in the populations studied by Reynolds et al. and Seller.

[Children with limb reductions in a population of 25,193 malformed newborns: the recognized causes. ECEMC. The Spanish Collaborative Study of Congenital Malformations]

OBJECTIVE

The purposes of this study were to analyze the causes of limb reduction deficiencies based on a clinical-epidemiological approach and to study the causes by clinical presentation.

PATIENTS AND METHODS

We have used the data from the Spanish Collaborative Study of Congenital Malformations (ECEMC) during the period from 1976 to 1996, which corresponded to more than 1,300,000 births. Among these, we identified 851 liver-born and 40 stillborn infants with limb reduction defects.

RESULTS

We could identify the cause in 177 (19.87%) of the 891 cases with limb reduction defects. In the analysis by clinical presentation, in 52.19% of the cases the limb deficiencies were the only defect present in the children (isolated), 30.75% presented multiple congenital anomaly patterns, and 17.06% were syndromes. The most frequent etiology was the genetic one.

CONCLUSIONS

First, most of infants with limb deficiencies have unknown cause and these defects are most frequently isolated malformations. On the other hand, the results of this analysis permitted the following considerations in relation to the guidance for the diagnosis of infants with limb reduction defects. If the child presents with multiple congenital anomalies (multiply malformed infant) a chromosomal analysis should be performed and it should be determined if the infant was prenatally exposed to a teratogenic agent. If these two aspects are normal, we should clinically analyze if the infant could have a known syndrome. In addition, since in our data 10.32% of isolated cases were due to autosomal dominant genes, a detailed clinical analysis of close relatives should be done to determine if some of them present mild limb deficiencies in order to provide an adequate information to the family.

Primary midline developmental field. II. Clinical/epidemiological analysis of alteration of laterality (normal body symmetry and asymmetry)

Lubinsky [Am J Med Genet 3:23-28, 1987] has suggested that the properties of the midline involve early determinative informational processes and are related to the midline's position and definition of the body's plane of symmetry. Opitz [Am J Med Genet 21:175-176, 1985, BD: OAS XXIX(1):3-37 1993] has pointed out that the laterality sequences represent a midline developmental field complex. Thus, bilateral left-sidedness (with asplenia) and bilateral right-sidedness (with asplenia) have been considered laterality sequences or syndromes if cause is known. Using the malformed infants registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC), we performed a clinical/epidemiological analysis of the relationship between midline defects and alteration of normal body asymmetry and symmetry. The results support the assumption that both conditions could be consequence of disturbances in the midline primary developmental field.

[Neonatal septic arthritis. Our experience in 14 cases (author's transl)]

A survey was carried out from october 1973 to december 1979 of fourteen newborn who presented septic arthritis secondary to sepsis, developed during their admission at our neonatology unit. Authors point out the high incidence of Klebsiella as the organism isolated in 48% of the positive cultures and the good response to general and local treatments. A discussion is done on the sequels and their long-term evolution.

[Transient neonatal diabetes (author's transl)]

A case of transient diabetes "mellitus" in a newborn infant with secondary hypertonic dehydration is presented. Authors review the problematical ethiology of this rare disease and a commentary is made on the adequate control of their case with continuous endovenous infusion of insulin.